Onestacked

End of the logfile after the crash ``` 2021-06-29 21:30:52 txin=CTxIn(COutPoint(b2783d6873df248f7d1ea4375cb0a910b12850654c2e074d3d7b7998cbb6f026, 1), scriptSig=473044022023af9c3e720c6a, nSequence=4294967294) 2021-06-29 21:30:52 IsFinalTx tx=8bbcf3ced37b8f57a4209a5b17743a2f6ca5669d0baf29c56abca8da602accaa --> FAILED 2021-06-29 21:30:52 txin=CTxIn(COutPoint(b2783d6873df248f7d1ea4375cb0a910b12850654c2e074d3d7b7998cbb6f026, 1), scriptSig=473044022023af9c3e720c6a, nSequence=4294967294) 2021-06-29 21:30:52 IsFinalTx tx=8bbcf3ced37b8f57a4209a5b17743a2f6ca5669d0baf29c56abca8da602accaa...

I created pastebins for the crash and the start ( I had to shorten a lot of repeating messages) Crash: https://pastebin.com/vLWDnnCj Start: https://pastebin.com/RFNDM097

Thank you, I will take a look at it!

I've noticed that STARTUPUE2 already is in xc/common/libraries/cells_xtra.xml: ```xml ``` Does that save me any work?

I've tried a bit but haven't really gotten far and then stopped working on it.

Alternative: Setup profiles (Probably as state messages) beforehand and then only refer to the profiles in the actual message. This would reduce message size, especially if later MSC's add more...

I've now added the config flag in bridgev2 and removed some changes not needed for bridgev2. I've tested this with element-hq/synapse#17705 and [MSC3861](https://github.com/matrix-org/matrix-spec-proposals/pull/3861). Requires msc3202_device_masquerading: true to be set in...

@tulir Can you approve the CI?

Can this be merged?

@tulir Friendly ping :)