Tunings and Temperaments (tuning.qml) plugin in Musecore 3 install

Hello, I would like to install this Tunings and Temperaments plugin (tuning.qml) and have done so in both plugin folders: once under /documents/musescore3/plugins and then also under program files/musecore3./plugins

but after restarting it does not appear in the plugin manager

Hallo, ich möchte gerne dieses Tunings and Temperaments plugin (tuning.qml) installieren und habe es in beiden plugin ordner getan: einmal unter /dokumente/musescore3/ plugins und dann auch noch unter programm files/musecore3./ plugins

aber nach neustart erscheint es nicht im plugin manager