diff --git a/README.md b/README.md
index 02175ee..ed08e34 100644
--- a/README.md
+++ b/README.md
@@ -82,6 +82,7 @@ Implementation notes
 - ZXDB integration uses Drizzle ORM over `mysql2` with a singleton pool at `src/server/db.ts`; API routes declare `export const runtime = "nodejs"`.
 - Entry and detail pages server‑render initial content and use ISR (`revalidate = 3600`) for fast time‑to‑content; index pages avoid a blocking first client fetch.
 - Database Schema: Repository queries include graceful fallback checks (via `information_schema.tables`) to remain functional even if optional tables (like `releases` or `downloads`) are missing from the connected MySQL instance.
+- Shared explorer UI components live under `src/components/explorer/` and power both `/zxdb` and `/registers` sidebars.
 
 Further reading
 - ZXDB details and API usage: `docs/ZXDB.md`
diff --git a/docs/ZXDB.md b/docs/ZXDB.md
index 88e4538..c8bf1ab 100644
--- a/docs/ZXDB.md
+++ b/docs/ZXDB.md
@@ -76,6 +76,7 @@ All endpoints are under `/api/zxdb` and validate inputs with Zod. Responses are
     - `sort` — `title` or `id_desc`
     - `scope` — `title`, `title_aliases`, or `title_aliases_origins`
     - `facets` — boolean; if truthy, includes facet counts for genres/languages/machines
+    - `machinetypeId` accepts a comma‑separated list (e.g. `27,26,8,9`) for multi‑select filters
 
 - Entry detail
   - `GET /api/zxdb/entries/[id]`
@@ -90,6 +91,13 @@ All endpoints are under `/api/zxdb` and validate inputs with Zod. Responses are
   - `GET /api/zxdb/languages` and `/api/zxdb/languages/[id]?page=1`
   - `GET /api/zxdb/machinetypes` and `/api/zxdb/machinetypes/[id]?page=1`
 
+- Search releases
+  - `GET /api/zxdb/releases/search`
+  - Query params:
+    - `q`, `page`, `pageSize`, `year`, `sort` — as used in the releases explorer
+    - `dLanguageId`, `filetypeId`, `schemetypeId`, `sourcetypeId`, `casetypeId`, `isDemo`
+    - `dMachinetypeId` accepts a comma‑separated list for multi‑select filters
+
 Runtime: API routes declare `export const runtime = "nodejs"` to support `mysql2`.
 
 ## Implementation notes
@@ -103,6 +111,7 @@ Runtime: API routes declare `export const runtime = "nodejs"` to support `mysql2
   }
   ```
 - Repository queries parallelize independent calls with `Promise.all` for lower latency.
+- When no machine filter is provided, the explorer prefers machine IDs `27,26,8,9` for sorting.
 
 ## Troubleshooting
 
diff --git a/docs/getting-started.md b/docs/getting-started.md
index c4abea1..ccda13d 100644
--- a/docs/getting-started.md
+++ b/docs/getting-started.md
@@ -36,3 +36,7 @@ Deployment shortcuts
   - pnpm deploy-test: push the current branch to test.explorer.specnext.dev
   - pnpm deploy-prod: push the current branch to explorer.specnext.dev
   - Ensure the corresponding Git remotes are configured locally before using these.
+
+Shared explorer UI
+- Reusable explorer layout/sidebar components live in `src/components/explorer/`.
+- These power both `/zxdb` and `/registers` filtering UIs.