ID's

ID's, which identify commands and are used when pressing the F1 key in the GIMP interface, are in https://git.gnome.org/browse/gimp/tree/app/widgets/gimphelp-ids.h

XML Tags Examples

procedure: in using/web.xml.

table: in toolbox/tools-painting.xml.

programlisting: in using/script-fu-tutorial.xml.

segmentedlist: in dialogs/path-dialog.xml for a n columns list.

Here is a diagram I often use.