Simple Rectangle has a radius on all edges ... strange

Maybe it has changed now, but a year ago the G64 setting was silently reset to nothing when e-stop was hit. So best to have the G64 in the g-code.

Well abort settings are another (related) issue.

Jerky motion but 'correct' parts sounds better to me but
wouldn't g64 p.001 for imperial and .01 for metric be better?

I think that gives a marked improvement for faster motion with a reasonable deviation IIUC.

that is what UCCNC does.... they have a g64 default setting for metric and another for imperial and I think they use 1 thou for imperial and 0.02 for metric as a default setting.

it does not matter what you do someone will moan as the plasma (blunt axe) guys will moan of overburn in the corners..... with those tolerance settings

really RTFM is the only answer

The idea is to minimize the unexpected problems.
We can't rely on everyone becoming a master of linuxcnc Gcode before using it.
The concept of G64 would be pretty alien to the casual user.
I think the g64 p.001 bridges the 'doesn't do anything crazy' with 'doesn't quite do what i want' reasonably.
And it seems UCCNC agrees.

Plasma is a very specialized form of CNCing and there are many weird things to it.
Phill works very hard to make that easier with Qtplasma for instance.

I presume we are just going to add it to the ini file

RS274NGC_STARTUP_CODE = G17 G20 G40 G49 G64 P0.001 G80 G90 G92 G94 G97 G98

no probs with me.

we should encourage people to learn a bit of gcode, as a new user I'd suggest you only need to know
G0, G1, G2, G3 , S, F M3, M4, M5
with the next one's being G4 G38.2, G92 and G64 and M2 + M30 and M6

the rest could be considered complex imo

the above ones get you understanding motion, and most or all of the motion a post processor would spit out

the next list is so that someone could change a tool, probe tool length set a tool length offset.

there should be some motivation to learn something how gcode makes the machine work.

No. I'm talking of linuxcnc's motion controller's initialized state.