gotr is a plugin to enable OTR support in the Gajim XMPP/Jabber client. It depends on potr (see afflux/pure-python-otr).
Place the gotr/ direcetory (found in src/) in your gajim's plugins
directory. This is usually found at one of the following locations:
$PREFIX/share/gajim/plugins/
$HOME/.local/share/gajim/plugins/
with $PREFIX being usually /usr or /usr/local.
After installing, the plugin must be manually enabled in the Gajim plugin interface.
Please read the FAQ before submitting your issue to the tracker.