The gtkrc file is generally located in
C:\Program Files\GIMP 2\share\gimp\2.0\themes or
C:\Users\[Username]\AppData\Roaming\GIMP\2.10\themes

It can also be found here: Edit > Preferences > Folders > Themes

This file customizes the user interface of Gimp. I have had trouble editing it. Could anyone give me some tips/information about editing this file. Mainly: *How to change theme colors for a custom theme *Resizing elements of the UI

Gimp themes have become very complicated, however if you want to start off with a quick-n-dirty hack put the attached theme odd-colors (unzip it first) in the Gimp profile themes folder.

To edit it, get a decent text editor, Notepad++ is the usual, and edit the gtkrc file.

It is set up with most entries "commented-out" and active entries using really horrible colors. (eg "#00FF00" is green)
50m second example: https://i.imgur.com/YDQIF7h.mp4

For cryptic parameters such as "fg[PRELIGHT] = ...." see https://wiki.gnome.org/Attic/GnomeArt/T ... /GtkThemes where it has explanations, but it is from 2013 and I think a little out-of date.

Font size: change the line font_name="Sans 14"
and
Dock icons size: the line gtk-icon-sizes = "gtk-menu=27,27"

You can not do any harm, when screwed up, just go back to a working theme