WebVTT subtitles missing from mkvmerge documentation
In the list of supported subtitle formats WebVTT is missing.
Also, in the "Output file formats" section in the documentation of mkvextract:
S_HDMV/TEXTST is listed, which seems to be different from
S_HDMV/PGS, so I suppose it should be listed in the documentation of mkvmerge as well.
S_DVBSUB is mentioned in the Mastroska Specification, but is nowhere to be seen in mkvmerge or mkvextract documentation.