diff --git a/subprojects/extensions-tool/man/gnome-extensions.txt b/subprojects/extensions-tool/man/gnome-extensions.adoc
similarity index 100%
rename from subprojects/extensions-tool/man/gnome-extensions.txt
rename to subprojects/extensions-tool/man/gnome-extensions.adoc
diff --git a/subprojects/extensions-tool/man/meson.build b/subprojects/extensions-tool/man/meson.build
index 643509c16..cca6fc49f 100644
--- a/subprojects/extensions-tool/man/meson.build
+++ b/subprojects/extensions-tool/man/meson.build
@@ -1,5 +1,5 @@
 custom_target('gnome-extensions.1',
-  input: ['gnome-extensions.txt', 'stylesheet.xsl'],
+  input: ['gnome-extensions.adoc', 'stylesheet.xsl'],
   output: 'gnome-extensions.1',
   command: [a2x, '-D', '@OUTDIR@', '--xsl-file', '@INPUT1@', '-f', 'manpage', '@INPUT0@'],
   install_dir: mandir + '/man1',