[pquki4]

Has there ever been notable instances of company regretting and reversing license change of a major project?

[pxc]

We're talking about an acquisition, not the original company making the reversal.

Red Hat used to routinely open-source acquisitions. Sun also did— that's how we got OpenOffice (and by way of it, LibreOffice). StarOffice was proprietary when Sun bought it.

[webwielder2]

Unity!

[toast0]

Oracle ended OpenSolaris although forks continue. Nokia and friends ended OpenSymbian, no forks afaik.

[baobun]

Lerna, if that's major enough for you.