This is an extensive re-do of the script.
# Added an 'Enable' setting
# Added support for multi-line insertions (comma delimited)
# Added insertions in a range of layers or a single insertion at a layer. Numbers are consistent with the Cura Preview (base1)
# Added frequency of Insertion (once only, every layer, every 2nd, 3rd, 5th, 10th, 25th, 50th, 100th)
# Added support for 'One at a Time' print sequence
I removed the period from the G-code to insert label for consistency. I also added a third option to this called "Skip layers". This allows you to insert gcode with a specific number of layers skipped (i.e. skip layers 1 will insert gcode every other layer, skip layers 3 will insert every fourth).
As an example, this change allowed me to insert a nozzle cleaning routine in my gcode without having to run it EVERY layer.
This spelling is in Ultimaker's style guide.
We use g-code, and capitalise the G if it's at the start of a sentence or header.
Pretty good score, considering there are literally thousands of user- or log-visible strings mentioning g-code across Cura.