the name of the format a source turned out to be written in.
This used to be a closed pair, XML or image. It is now whatever is registered, so that a
format the loader has never heard of can identify itself; the two built-ins go on reading the
documents they always did.
the name of the format a source turned out to be written in.
This used to be a closed pair, XML or image. It is now whatever is registered, so that a format the loader has never heard of can identify itself; the two built-ins go on reading the documents they always did.