builds.sr.ht: drop 9front support

builds.sr.ht/compatibility.md

@@ -1218,42 +1218,3 @@ spaces), where `url` is the URL of the package repository, `release` is e.g.
 repositories:
   sr.ht: https://mirror.sr.ht/debian/sr.ht/ cosmic main DEADBEEFCAFEF00D
 ```
-
-## 9front
-
-Maintainer: Drew DeVault <sir@cmpwn.com>
-
-Support cycle: no support guarantees are made for 9front
-
-<table class="table table-sm table-hover">
-  <thead>
-    <tr>
-      <th>9front "NO THINKPAD"</th>
-      <th colspan="3" style="font-weight: normal; text-align: center">
-        <code>image: 9front</code>
-      </th>
-    </tr>
-    <tr>
-      <th>arch</th>
-      <th style="text-align: center">supported</th>
-      <th style="text-align: center">native</th>
-      <th>updated</th>
-    </tr>
-  </thead>
-  <tbody>
-    <tr class="table-primary">
-      <td><code>arch: pc64</code> (default)</td>
-      <td style="text-align: center; color: green">✓</td>
-      <td style="text-align: center; color: green">✓</td>
-      <td>manually</td>
-    </tr>
-  </tbody>
-</table>
-
-**Caveats**
-
-- Git submodules are not supported by git9
-- 9front ships a dated Mercurial version which is not compatible with hg.sr.ht's
-  wire protocol
-- Custom packages and custom repositories are not supported
-- Shell access is not supported