Documentation listed "Myinfo" extension as a dependency yet doesn't exist...How would someone go about installing this extension?
A good question. Do you @SamanthaNguyen: happen to know how to get to that code?
I now archived this extension. It is pointless to have it here.
As for the actual concern, the MyInfo extension very much exists and has existed since 2008 at ShoutWiki; it's largely a wrapper around the ull Featured PHP Browser Detection & OS Detection script, but indeed, it's not (yet) open source.
Regardless, even without MyInfo installed, EnhanceContactForm **does** provide more details about the wiki where the report was sent: its DB name (`$wgDBname`), URL (`$wgServer`) and the reporter's IP address. IIRC only the last one is one that Special:Contact can be natively configured to send (and it certainly wasn't the case when EnhanceContactForm was originally written).