Can't open/edit layout since 2.2.3 patch or lastest debian update

We think this might be a translations issue as described here:

Basically an upstream translator put some " in the translations which got included when we released - we have had to change the code to accommodate.

Can you temporarily try running the CMS in English to confirm? If so, 2.3 does not have this issue and we’d recommend upgrading to that if you can