# 260613 — XWiki deep dive (implementation, extension interfaces, ecosystem)

Date: 2026-06-13

## What this is

A focused study of **XWiki** — the canonical "wiki-as-application-platform"
engine flagged in `research/260608-wikiengines-overview/`. Goes past the landscape
scan into XWiki's **implementation** (component/DI architecture, document data
model, storage, rendering, events), the **interfaces it exposes to extend the core
engine** (components, macros, UI extension points, script services, REST), and the
**extension ecosystem** (extensions.xwiki.org repository, XAR/JAR/WebJar types,
notable extensions).

Read through one lens: **what does XWiki teach shard-wiki about (a) adapting a
structured app-platform engine as a shard, and (b) how a host engine can become
federation-capable through its own extension mechanism** (INTENT *composable
integration*).

Complements:
- `research/260608-wikiengines-overview/` — the landscape scan that surfaced XWiki
- `research/260608-federation-concepts/` — already covered XWiki's ActivityPub extension

## Contents

| Path | Role |
|------|------|
| `findings.md` | Architecture, extension-interface catalog, ecosystem, capability profile, INTENT mapping, UC seeds, sources |

## Status

Initial deep dive complete. Two new use cases promoted to
`spec/UseCaseCatalog.md` (UC-38, UC-39); existing UC-34/UC-36/UC-31 enriched with
XWiki specifics. Adapter-contract implications feed
`workplans/SHARD-WP-0002-federation-architecture.md`.