diff --git a/hosts/common/programs/firefox.nix b/hosts/common/programs/firefox.nix
index 64672efbf..d503e4b8d 100644
--- a/hosts/common/programs/firefox.nix
+++ b/hosts/common/programs/firefox.nix
@@ -374,13 +374,11 @@ in
           // configure which extensions are visible by default (TODO: requires a lot of trial and error)
           // defaultPref("browser.uiCustomization.state", ...);
 
-          // auto-open mpv:// URIs without prompting.
-          // can do this with other protocols too (e.g. matrix?). see about:config for common handlers.
-          defaultPref("network.protocol-handler.external.mpv", true);
-          // element:// for Element matrix client
-          defaultPref("network.protocol-handler.external.element", true);
-          // matrix: for Nheko matrix client
-          defaultPref("network.protocol-handler.external.matrix", true);
+          // auto-open specific URI schemes without prompting:
+          defaultPref("network.protocol-handler.external.xdg-open", true); // for firefox-xdg-open extension
+          defaultPref("network.protocol-handler.external.mpv", true); // for open-in-mpv extension
+          defaultPref("network.protocol-handler.external.element", true); // for Element matrix client
+          defaultPref("network.protocol-handler.external.matrix", true); // for Nheko matrix client
         '';
         # instruct Firefox to put the profile in a predictable directory (so we can do things like persist just it).
         # XXX: the directory *must* exist, even if empty; Firefox will not create the directory itself.