Embedding JIra into a third party app legal restrictions?

Hi,

I read a lot of years ago that it is not permitted embedding Jira into a 3rd party app. Unfortunately, I’m now unable to find that Atlassian’s document.

Might anyone share a link to some official document explaining the concepts and the limits for that?

Don’t panic, we will not do anything illegal. We only want to avoid waste our time working on some things.

Thanks in advance,
Pablo