This is not a very useful api, and if you need it, you can just as easily keep track yourself which thread called gtk_init().
The calls used old bugzilla URLs and nobody cared about that. So apparently they are very unused. There's also a potential conflict between gitlab and bugzilla URLs and what base bug to use there. The old usages have been converted to comments.
This utility function can be useful to know which thread was initialized for GTK+.
This utility function can be useful to check whether GTK+ was already initialized or not.