[Cthulhu_]

I've found most deadlines I've worked with to be internal. The only exceptions to that however was legislation dates; Cookie walls and GDPR, new laws for stock trading on an European level (forgot the name), things like that. These are things for which your company can be fined heavily for. Other deadlines are likely to be of the "we'll start earning money later" variety.

[ozim]

Those are BS as well. No one is going to fine company on day 1 of a new law. GDPR was effective 25 may 2018 but companies still had half of a year to implement it.

Basically if you prove you are working on it I bet they will let you off the hook.

[Tade0]

I have one additional type of external deadline:

"The marketing campaign already promised it would be ready by X"