On the other hand, Libtaginfo , a library for reading media metadata (tags), which was used by Xnoise and developed by the same Shuerhaaken, will not be abandoned.

Xnoise is free, open source software so even though its developer won't be maintaining it any more, it doesn't mean it's dead yet: if there are Xnoise users out there who can continue its development, contact Shuerhaaken on the Xnoise mailing list and see if you can take over the project.