Cross-source identifiers
Every current identifier attachment, with the link method and confidence carried verbatim — deterministic links are 1.000; probabilistic links surface their real matcher confidence, never rounded up.
| Scheme | Value | Source table | Link method | Confidence | Since | Provenance |
|---|---|---|---|---|---|---|
| npi | 1760571939 | nppes_providers | deterministic_pk | 1.000 | 2026-06-10 | evidencerecorded: 2026-06-10 methodology: entity-graph/v1 evidence: {"rule":"D-NPI","source_pk":"1760571939","entity_type_code":"2"} |
| pac_id | 4183883325 | pecos_providers | exact_npi_in_pecos | 1.000 | 2026-06-16 | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 evidence: {"npi":"1760571939","rule":"D-PECOS","enrlmt_id":"O20120308000164","pecos_asct_cntl_id":"4183883325"} |
| pecos_enrlmt_id | O20120308000164 | pecos_providers | exact_npi_in_pecos | 1.000 | 2026-06-16 | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 evidence: {"npi":"1760571939","rule":"D-PECOS","enrlmt_id":"O20120308000164"} |
Graph edges
One-hop relationships — ownership, chain membership, operation — each backed by a federal source row.
| Relationship | Entity | Confidence | Source table | Provenance |
|---|---|---|---|---|
| ← owns | ALAN D MATHIOS | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"10/01/2020","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"0244649598","source_pk":116204,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | CHARLES ACKERMAN | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2023","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"0345771184","source_pk":116207,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | DONALD D WILSON | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2020","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"1153730403","source_pk":116210,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | PETER DUGO | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2023","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"1254862097","source_pk":116213,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | MARY ANN ERICKSON | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2018","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"1557607736","source_pk":116216,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | OWNER PAC 1557862950 | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"72","association_date":"12/07/2016","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"1557862950","source_pk":116219,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"72","role_text_owner":"ADP OF THE SNF","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | STEPHEN C NUNLEY | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2022","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"1658743919","source_pk":116220,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | RUTH A BRADLEY | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2025","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"1658872049","source_pk":116223,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | OWNER PAC 1658872056 | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"72","association_date":"01/01/2019","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"1658872056","source_pk":116226,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"72","role_text_owner":"ADP OF THE SNF","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | FRIENDS SERVICES FOR THE AGING (PA) | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"43","association_date":"01/01/2015","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"1759805286","source_pk":116227,"type_owner":"O","enrollment_id":"O20120308000164","role_code_owner":"43","role_text_owner":"OPERATIONAL/MANAGERIAL CONTROL","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | JOE C MAREANE | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2024","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"2062844483","source_pk":116229,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | SONIA R RUCKER | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2024","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"2163953902","source_pk":116232,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | MEGAN FRETTO | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"41","association_date":"07/07/2025","percentage_ownership":0} evidence: {"rule":"D-OWNER","owner_pac":"3476054875","source_pk":116235,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"41","role_text_owner":"CORPORATE DIRECTOR","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":0,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | MICHAEL C YOUMANS | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"43","association_date":"07/09/2025","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"4183908551","source_pk":116238,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"43","role_text_owner":"OPERATIONAL/MANAGERIAL CONTROL","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | GREGORY SOMMERS | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"09/09/2014","percentage_ownership":0} evidence: {"rule":"D-OWNER","owner_pac":"4284663758","source_pk":116240,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":0,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | AUSTEN HOLOCHAK | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"41","association_date":"07/07/2025","percentage_ownership":0} evidence: {"rule":"D-OWNER","owner_pac":"4385145788","source_pk":116243,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"41","role_text_owner":"CORPORATE DIRECTOR","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":0,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | AFFINITY REHABILITATION LLP (SC) | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"72","association_date":"12/07/2016","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"4789843376","source_pk":116246,"type_owner":"O","enrollment_id":"O20120308000164","role_code_owner":"72","role_text_owner":"ADP OF THE SNF","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | DAVINA A DESNOES | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2020","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"4981013232","source_pk":116247,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | WILLIAM CRANE | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2021","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"5294021812","source_pk":116250,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | ALAN PEDERSON | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2018","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"5294916227","source_pk":116253,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | LUCY H STALEY | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2020","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"5890104145","source_pk":116256,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | CHRISTINE SHEPPARD | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2023","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"5890226633","source_pk":116259,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | JEFFREY O PENOYER | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2023","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"6507107331","source_pk":116262,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | JUDITH A EHREN | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2021","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"7517376866","source_pk":116265,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | OWNER PAC 7618478009 (WI) | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"72","association_date":"04/15/2025","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"7618478009","source_pk":116268,"type_owner":"O","enrollment_id":"O20120308000164","role_code_owner":"72","role_text_owner":"ADP OF THE SNF","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | OWNER PAC 7911408315 | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"72","association_date":"12/07/2016","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"7911408315","source_pk":116269,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"72","role_text_owner":"ADP OF THE SNF","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | HELEN TALTY | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"04/01/2021","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"8426467770","source_pk":116270,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | OWNER PAC 8527569912 (WI) | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"72","association_date":"04/15/2025","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"8527569912","source_pk":116273,"type_owner":"O","enrollment_id":"O20120308000164","role_code_owner":"72","role_text_owner":"ADP OF THE SNF","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | LAURIE J MANTE | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"41","association_date":"11/11/2019","percentage_ownership":50} evidence: {"rule":"D-OWNER","owner_pac":"8628077567","source_pk":116274,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"41","role_text_owner":"CORPORATE DIRECTOR","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":50,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | BANK OF NY MELLON (NY) | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"72","association_date":"09/01/2023","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"8820907009","source_pk":116277,"type_owner":"O","enrollment_id":"O20120308000164","role_code_owner":"72","role_text_owner":"ADP OF THE SNF","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | JACOB SKEZAS (NY) | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"43","association_date":"08/01/2019","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"9234324450","source_pk":116278,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"43","role_text_owner":"OPERATIONAL/MANAGERIAL CONTROL","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | JEFFREY W LAYTON | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"40","association_date":"01/01/2019","percentage_ownership":5} evidence: {"rule":"D-OWNER","owner_pac":"9335558683","source_pk":116280,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"40","role_text_owner":"CORPORATE OFFICER","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":5,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | TOMPKINS COMMUNITY BANK (NY) | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"72","association_date":"08/19/2025","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"9436650827","source_pk":116283,"type_owner":"O","enrollment_id":"O20120308000164","role_code_owner":"72","role_text_owner":"ADP OF THE SNF","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
| ← owns | OWNER PAC 9739680133 | 1.000 | snf_all_owners | evidencerecorded: 2026-06-16 methodology: entity-graph/v1 attributes: {"role_code":"72","association_date":"12/07/2016","percentage_ownership":null} evidence: {"rule":"D-OWNER","owner_pac":"9739680133","source_pk":116284,"type_owner":"I","enrollment_id":"O20120308000164","role_code_owner":"72","role_text_owner":"ADP OF THE SNF","dst_resolved_via":"pecos_enrlmt_id","percentage_ownership_raw":null,"enrollment_organization_name":"KENDAL AT ITHACA"} |
Current record
Current claims returned for this entity, grouped by provenance subject. The table exposes the source identifier recorded for each claim.
org · 1760571939 JSON
| Metric | Value | Asserted | Source |
|---|---|---|---|
| enumeration_date | 2006-10-12 | 2026-06-10 | Centers for Medicare & Medicaid ServicesNPPES NPI Registry (individuals) 202602 publisher: Centers for Medicare & Medicaid Services retrieved: 2026-06-10 sha256: 8b5267e250fd4df6… claim API: JSON |
| legal_business_name | KENDAL AT ITHACA | 2026-06-10 | Centers for Medicare & Medicaid ServicesNPPES NPI Registry (individuals) 202602 publisher: Centers for Medicare & Medicaid Services retrieved: 2026-06-10 sha256: 8b5267e250fd4df6… claim API: JSON |
| practice_state | NY | 2026-06-10 | Centers for Medicare & Medicaid ServicesNPPES NPI Registry (individuals) 202602 publisher: Centers for Medicare & Medicaid Services retrieved: 2026-06-10 sha256: 8b5267e250fd4df6… claim API: JSON |
| primary_taxonomy | 314000000X | 2026-06-10 | Centers for Medicare & Medicaid ServicesNPPES NPI Registry (individuals) 202602 publisher: Centers for Medicare & Medicaid Services retrieved: 2026-06-10 sha256: 8b5267e250fd4df6… claim API: JSON |
Provider screening signals
NPI-keyed source families read directly for 1760571939: federal and state integrity lists, CMS Open Payments, Order and Referring eligibility, Medicare opt-out, and enrollment revalidation. Cells expose the source and provenance fields supplied by the selected record. A screening aid — re-confirm any match against the primary source before acting; absence means nothing on file in the data Fonteum currently holds, never a guarantee none exists.
Sanctions & integrity
Coverage staleExclusion coverage is stale or cannot be reconciled to an attested source artifact. This result is indeterminate and must not be treated as a clearance; check the current issuing-agency lists.
- Coverage status: indeterminate
- Screened 26 integrity lists; no negative determination was made.
14-tuple provenance (26)
Industry payments
None on file0 CMS Open Payments records on file for this NPI.
14-tuple provenance (1)
Order & referring eligibility
None on fileNo CMS Order and Referring record on file for this NPI.
14-tuple provenance (1)
Medicare opt-out
None on fileNo CMS Medicare opt-out affidavit on file for this NPI.
14-tuple provenance (1)
Revalidation
On file1 Medicare enrollment record on file.
- Due date: TBD upstream — not due within the ensuing six months.
14-tuple provenance (1)
Point-in-time
Query retained claim coordinates under bitemporal-read/v1. Most facts have no superseded row; dates outside retained coverage may return no prior version, and diffs require both coordinates.
Pick a date to reconstruct, or two dates to diff. Equivalent JSON: /api/v1/history/{subject_type}/{subject_id}?at=… and …/diff?from=…&to=…