Extruder jog with M291 command?

[Nappen]

I was building a purge macro and found that it was possible to add jog buttons for xyz but not for extruders?

would be nice to have the possibility to run the extruder there as well.
so u could have say

G1 E50 f600
M291E P"message" R"message S3
G1 E-6.5 f600
M400
M292

so if u swap a filament and it did not fully clear out the old colour u could purge more in the message jog and then press ok to complete it.