In order to have "Blender" Key-config Preset with Set Origin, what is the python Identifier for Select With?

I prefer the "Blender 27X" Key-config Preset because I’m more used to it, but i want to change to the "Blender" Key-config Preset, so for instance i won’t accidentally tell people to use wrong/outdated/non-default keys, which has happened on occasion : )

A lot of operators are not defined in the "Blender" Key-config Preset python file (or a copy made by exporting the presets), so i can’t map them in Blender.

As a work-around i can look up the Identifier "Blender 27X" Key-config Preset, find the relevant code in the python file and paste it in my modified "Blender" Key-config Preset. (I do this mainly for Set Origin which i rather not do without.)

The "Blender 27X" Key-config Preset allows for Right Clicking in the 3D Viewport to select something. But with the "Blender" preset it is set to left click, but can’t be remapped in Blender. So i also wanted to copy-past that behaviors in my modified "Blender" preset. But in the Preferences it does not show an Identifier as with other operators. So now i don’t know how to easily find it in the 11000+ lines long python file (or if it is there at all).

On a side note: My exported "Blender" preset python file lists only a fraction of the operators. I find it quite confusing that some of the operators not there can be mapped in Blender and others can’t.

Any info on this, on my problem, or possibly a different solution to missing Set Origin in the "Blender" preset, is welcome. : )