These unstable:* shapes are documented only for the included examples. They are
not core requirements and are not a program, eligibility, or admission-selection
API. Consumers may ignore them. Broad implementation requires a separate reviewed
extension contract and schema; no generic validator may require that support.
| Key | Illustrative shape | Core fallback |
|---|---|---|
unstable:components |
Array of objects with name, starts_at, and location-shaped location. Dates retain original precision. |
Overall description and registration/venue instructions identify which days have which attendance modes. No ticket coverage inferred. |
unstable:eligibility |
Object with integer minimum_age, maximum_age. |
Belgrade registration instructions state ages 18–26. |
unstable:participation |
Object with integer minimum_team_size, maximum_team_size, boolean individual_matching_available, text prerequisite. |
Registration instructions state team sizes, matching, and prior conference attendance. |
unstable:event_languages |
Object with arrays working and presentations of language tags. |
Belgrade description names Serbian and English. Document language remains English. |
unstable:broadcast |
Object with URL recordings_url and boolean counts_as_attendance. |
FOSDEM description says recordings remain available; core location remains physical. |
No extension may change the meaning of the core. Stripping every extension must leave an accurate useful listing, though automation loses detail. Weekly visiting hours are described in museum instructions. Structured opening-hours expansion is outside the core contract.