the state is saved. The function can save other state, modify values before
they're saved, etc.
-### displaytime
-
- hook(type => "displaytime", id => "foo", call => \&display);
-
-This hook can be registered to override the regular `displaytime` function.
-Only the last displaytime hook will be used.
-
### renamepage
hook(type => "renamepage", id => "foo", call => \&renamepage);
It's ok if this is not implemented, and throws an error.
+#### `rcs_test_receive()`
+
+This is used to test if changes pushed into the RCS should be accepted.
+Ikiwiki will be running as a pre-receive hook (or equivilant) and should
+examine the incoming changes, decide if they are allowed, and communicate
+that to the RCS.
+
+This is optional, and doesn't make sense for all RCSs.
+
### PageSpec plugins
It's also possible to write plugins that add new functions to