I can reproduce this on a fresh beta 5.3 installation with only jrDeveloper, jrEmbed and jrUpimg additional modules installed.
I previously posted about seeing this error here:
https://www.jamroom.net/the-jamroom-network/forum/using-jamroom/30696/embed-local-media-error
Bare bones clean beta 5.3 installation.
Add and enable the jrDeveloper, jrEmbed and jrUpimg modules. Allow on the example quota.
Visit the admin blog, edit the blog post, click the Embed Local Media button.
The modal opens with a single upload image tab showing the error:
{"notices":[{"type":"error","text":"invalid module"}]}
I can fix this by going to mysite.com/embed/admin/global and clicking save, after which the upload image tab shows without an error.
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¯\_(ツ)_/¯ Education, learning resources, TEL, AR/VR/MR, CC licensed content, panoramas, interactive narrative, sectional modules (like jrDocs), lunch at Uni of Bristol. Get in touch if you share my current interests or can suggest better :)