In Chrome, can't open a .c3p created in Opera

Since cloud saving is somehow bugged and not working for me in Opera (going to have to post separately about that I guess), I downloaded Chrome in order to continue working on my project and hopefully gain the ability to actually save to cloud as it is intended.

But C3 on Chrome refuses to open the project I started on Opera. I'll get this prompt:

The project is still opening using Opera as expected. I thought these files are universally compatible, no matter what browser or device you use C3 on.

It should work. Opera also uses the same browser engine as Chrome (Chromium). It's hard to say more without more information though.

This is now happening for me using newest Opera beta as well.

It begs the rather unnerving question; are projects older than Chromium version 85 confirmed to work on version 85 (and beyond) at all? Then again, I guess there would be more threads about it on here, huh.

Even if this issue is only on my end - to me it's disconcertingly beginning to reinforce the fact that using a browser to run the game engine is just another way something may or may not break with any given update.

What kind of additional information do you need? I have this issue on newest Opera beta, newest stable release of Chrome, newest Construct 3, newest Windows 10 update.

Chromium browser doesn't work either.

If you run in to a bug or issue in Construct 3, please post it to the GitHub issue tracker here:

github.com/Scirra/Construct-3-bugs

You must follow the bug report guidelines or your issue will be closed without investigation.

Projects should open regardless of which browser, or which version of the browser, is saving or opening the project. The file format has nothing to do with the browser engine and doesn't change at all depending on it. So it should always work. As Kyatric noted we'd need all the information requested in a bug report to be able to help.