To clarify - this will not affect anything other than Nightly, as the background hang monitor is not enabled on anything other than Nightly. (I am not familiar with whether the status-firefoxN flags are intended to be edited by anyone, so I'm not going to mess with that.)
Gabriele, if you personally ran into this, do you happen to still have the profile that caused it? I'm specifically interested in the
last_permahang.bin file which ought to be in the root of the profile directory, if you have it.
I need to update the
MOZ_CRASH("Unsupported HangEntry type?"); line to be a soft failure, but with 17 crashes this doesn't look like a randomly corrupted file, but more like a bug during the writing of the file.