xterm is (arguably) implementing ECMA-48 wrong: replies to out-of-band strings (such as OSCs) should themselves be marked as out-of-band (by embedding them in a

xterm is (arguably) implementing ECMA-48 wrong: replies to out-of-band strings (such as OSCs) should themselves be marked as out-of-band (by embedding them in an OSC/APC/DCS/PM, terminated with ST not BEL). Instead it is replying to an out-of-band command in-band. However, I think the design of the Unix tty subsystem is also at fault here - out-of-band messages (OSC/APC/DCS/PM) should be filtered out by default and only delivered to processes which explicitly declare that they are expecting them. That said, if zsh is putting the tty in raw mode, it is saying it wants everything the terminal will send it, so it needs to do that filtering itself.