Drupal 11 adds a "Machine name" column in field_ui.

For now I am using the class 'machine-name' for feature detection.
Ideally, core should provide a better way for contrib modules to detect if the machine name column is present.

Moving to 8.x branch (other two are not supported) - will check soon, had no idea this was added.

had no idea this was added.

Yeah this is quite new and not part of any stable release yet if I saw correctly.
I only found it because I really wanted to have machine names.

Perhaps core should provide better detectability of this change, before anything is committed to ds or field_group.
Until then, people can use this patch if it is useful to them.

It needs to be added for the DS fields as well. Since it's only in D11, we can also just do this for detection:

(int) Drupal::VERSION >= 11

Will work on this one later this day

merged!