See the commit 28467cb on the gimp-data-extras repo where I moved this
data in. Not sure why this metadata file was ever pushed to the main
repo as it is obviously for the data-extras package (or else I am
missing some information!).
The old 2017 report where it was originally added:
https://bugzilla.gnome.org/show_bug.cgi?id=763398
I completely forgot to rename the appstream file according to the new
ID. While doing so, I also make it a .in.in file, with initial
processing by the autotools. Indeed I need @GIMP_COMMAND@ to be replaced
by AC_CONFIG_FILES().
Finally I fix a badly closed XML tag (which reminds me I should always
test a commit, even when it's a simple non-C 1-liner change!).
Jehan