I can’t found it how can I post embedded videos or posts from social media sites, like on Reddit or other similar sites.
It’s blocked by CSP
What’s CSP?
Content Security Policy, this defines which domains may be used from the main site domain, this blocks different kinds of attacks but has the effect that random domains cannot be embedded
So it can be solved by whitelisting known safe domains such as catbox.moe who provides sharing media and such!
that would be possible, it would require “trusted” embed sources, e.g. youtube or catbox or whatever. i know of another reddit type clone site which has their own official video host and pic host that allow embed but they block others
this would have to be the same on all instances for federated articles to work, so that would be a problem
content security policy
Do the videos show up for you here? (For me it’s only unsupported media type but in principle it seems like markdown could work too)