I've already done a few exports into Hugo and static sites, locally, for backing up posts via their API. Just about everyone I know already hacks their tumblr theme.
You can already add Google Analytics but a GTM container isn't something that's easy to do.
I suspect what we're going to start to see is Tumblr Labs being taken over by plugins!
In the past, I've used Greasemonkey and an independently made add-on for Chrome that let me futz about with functionality in Tumblr. It'd be nice to affect functionality without having to hack JS to do it.
You can export your Tumblr into Hugo?
BTW. Do you know how to share stuff that I like from IG to Tumblr?
I've used Tumblr for art and photography now it's a desert. Photography has moved to IG which is a horrible place to appreciate pictures.
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