I am uploading a NMU to DELAYED/10 in order to fix this.
The debdiff is attached.
diff -Nru gnome-icon-theme-yasis-0.4.2/debian/changelog
gnome-icon-theme-yasis-0.4.2/debian/changelog
--- gnome-icon-theme-yasis-0.4.2/debian/changelog 2023-09-29
11:37:49.000000000 +0200
+++ gnome-icon-theme-yasis-0.4.2/debian/changelog 2023-09-29
11:36:02.000000000 +0200
@@ -1,3 +1,10 @@
+gnome-icon-theme-yasis (0.4.2-1.3) unstable; urgency=medium
+
+ * Non-maintainer upload.
+ * Convert to source format 3.0. (Closes: #1043165)
+
+ -- Bastian Germann <b...@debian.org> Fri, 29 Sep 2023 11:36:02 +0200
+
gnome-icon-theme-yasis (0.4.2-1.2) unstable; urgency=medium
* Non-maintainer upload.
diff -Nru gnome-icon-theme-yasis-0.4.2/debian/source/format
gnome-icon-theme-yasis-0.4.2/debian/source/format
--- gnome-icon-theme-yasis-0.4.2/debian/source/format 1970-01-01
01:00:00.000000000 +0100
+++ gnome-icon-theme-yasis-0.4.2/debian/source/format 2023-09-29
11:36:02.000000000 +0200
@@ -0,0 +1 @@
+3.0 (quilt)
