When rebuilding, I see
building recentchanges/change_63476fba3a519d42ee56c7611250ada41111356d._change, which depends on templates/page.tmpl
building recentchanges/change_bd07c4308d5eea2cd27ad067a502318dc0e9c8bb._change, which depends on templates/page.tmpl
building recentchanges/change_6c2a66b022276951d79f29c1221d22fe1592f67f._change, which depends on templates/page.tmpl
building recentchanges/change_f08669f128d618d0da460234b2cee555b0818584._change, which depends on templates/page.tmpl
building recentchanges/change_b0347df66da5c515dc0d1d612ecdfbe203a0a674._change, which depends on templates/page.tmpl
building recentchanges/change_0bb246c481e9ede8686f6caa4de40b9e94642e40._change, which depends on templates/page.tmpl
building recentchanges/change_511846ca75fb2e87fb90582ead282d104a5e13fc._change, which depends on templates/page.tmpl
...
Are these accidentally committed gibberish? If so, how to remove them properly?
They are little per-change pages that are inlined together to produce your RecentChanges page.
(They're not committed to git, only stored internally.)