Sorry if this's been posted before, but I do not know how to search this forum.
It just searches the whole itch.io website.
i have report feedback to itch.io and leaf say
In the meantime you can use google to search what they have indexed, using a query like: some topic inurl:itch.io/t
here a example, now im searching ads for superpower, so i write like this into google
ads superpower inurl:itch.io/t