This soundfont contains the metronome clicks from Ardour/MusE/MuseScore so that they can be embedded into a score, for example to “count in” or to add a “click track”.
Put in MIDI note 76 (E₅) for a “tick” at velocity 127 for “downbeats” (first beat of a measure) and MIDI note 77 (F₅) for a “tack” at velocity 127 in stressed beats (e.g. the third in a 4/4 time signature), at velocity 80 for unstressed beats (e.g. the second and fourth in a 4/4 time signature). In MuseScore this can be applied to a regular instrument or a “Wood Blocks” unpitched percussion stave.
See http://www.mirbsd.org/permalinks/wlog2020_e20210424.htm for further information, pictures and a table!
The SoundFont is actually CC0-licenced (whose § 2 does not apply because I cannot legally waive copyright in my legislation) in what parts copyright law does apply but that’s pretty much the same as PD and the actual samples are PD because they’re mathematically generated and don’t contain enough creativity to pass threshold of originality and are thus not copyrightable.
MuseScore_General (both LQ and HQ) 0.2.1 and later incorporate these samples as well, see: https://musescore.org/en/node/154666#comment-1097877