According to the bash manual (emphasis mine):
The value is the prompt printed before the command line is echoed when the -x option is set (see The Set Builtin). The first character of PS4 is replicated multiple times, as necessary, to indicate multiple levels of indirection. The default is ‘+ ’.
Is there a way to disable this behavior? I thought of cursor left (
\b), but bash seems to only consider the literal first character (