diff --git a/mail-client/thunderbird/metadata.xml b/mail-client/thunderbird/metadata.xml
index e281b042c5287..ceafcda1bba6c 100644
--- a/mail-client/thunderbird/metadata.xml
+++ b/mail-client/thunderbird/metadata.xml
@@ -28,9 +28,9 @@
 		instead of bundled.</flag>
 	<flag name="system-libvpx">Use the system-wide <pkg>media-libs/libvpx</pkg>
 		instead of bundled.</flag>
+	<flag name="system-png">Use the system-wide <pkg>media-libs/libpng</pkg>
+		instead of bundled (requires APNG patches)</flag>
 	<flag name="system-webp">Use the system-wide <pkg>media-libs/libwebp</pkg>
 		instead of bundled.</flag>
-
-
 </use>
 </pkgmetadata>
diff --git a/mail-client/thunderbird/thunderbird-78.13.0.ebuild b/mail-client/thunderbird/thunderbird-78.13.0-r1.ebuild
similarity index 100%
rename from mail-client/thunderbird/thunderbird-78.13.0.ebuild
rename to mail-client/thunderbird/thunderbird-78.13.0-r1.ebuild
diff --git a/mail-client/thunderbird/thunderbird-78.14.0.ebuild b/mail-client/thunderbird/thunderbird-78.14.0-r1.ebuild
similarity index 100%
rename from mail-client/thunderbird/thunderbird-78.14.0.ebuild
rename to mail-client/thunderbird/thunderbird-78.14.0-r1.ebuild
diff --git a/mail-client/thunderbird/thunderbird-91.3.0.ebuild b/mail-client/thunderbird/thunderbird-91.3.0-r1.ebuild
similarity index 100%
rename from mail-client/thunderbird/thunderbird-91.3.0.ebuild
rename to mail-client/thunderbird/thunderbird-91.3.0-r1.ebuild
diff --git a/mail-client/thunderbird/thunderbird-91.3.1.ebuild b/mail-client/thunderbird/thunderbird-91.3.1-r1.ebuild
similarity index 100%
rename from mail-client/thunderbird/thunderbird-91.3.1.ebuild
rename to mail-client/thunderbird/thunderbird-91.3.1-r1.ebuild
diff --git a/mail-client/thunderbird/thunderbird-91.3.2.ebuild b/mail-client/thunderbird/thunderbird-91.3.2-r1.ebuild
similarity index 100%
rename from mail-client/thunderbird/thunderbird-91.3.2.ebuild
rename to mail-client/thunderbird/thunderbird-91.3.2-r1.ebuild
diff --git a/mail-client/thunderbird/thunderbird-91.4.0.ebuild b/mail-client/thunderbird/thunderbird-91.4.0-r1.ebuild
similarity index 100%
rename from mail-client/thunderbird/thunderbird-91.4.0.ebuild
rename to mail-client/thunderbird/thunderbird-91.4.0-r1.ebuild