2023-07-03 — updated 2023-10-04

It doesn’t seem well known these days, but the classic ResEdit Application can be extended to add additional functionality by adding TMPL, RSSC, and PICK resources to either the ResEdit Preferences file or ResEdit itself.


An RSSC-based editor for Apple Event Terminologies. I don’t really know anything about this one, but:

aete Editor for ResEdit


A decompiler RSSC that can be installed into ResEdit to more easily view assembly without needing an external program, CODE Editor:

CODE Editor for ResEdit 2.1


A TMPL which adds support for the gbly resource, which controls system patching support for machines(?):



A TMPL which adds support for gusd, used to define the supported devices for a System file using the gestalt ID. For instance, it’s common to make changes to this when using a IIsi ROM with an SE/30 to enable 32-bit clean support. Instead of the typical process of editing raw hex, you can install this TMPL to add native support to the ResEdit UI:


For instance, when following Gamba’s proceedure to install the OS on an SE/30 with a IIsi ROM, you can easily modify gestalt 9 from 3 to 5 instead of performing a more delicate hex modification. Otherwise follow the normal steps.