I will try to collect as much as information and place it here. Maybe something can be done with Matrix or IRC or via an app on GitHub pages but that is no priority atm. If you want contact me at Discord (derberg#7221) and I will answer questions and may add you to a group where I will add everybody that asks for it..
URLs:
Discord: https://discord.gg/0z7IGZ5Sv3D0mEN0
Matrix: https://matrix.to/#/+custom-3ds-assets:matrix.org
System Settings customization tutorial: https://gbatemp.net/threads/customize-your-system-settings-app.492960/
System Settings customization documentation: https://docs.google.com/spreadsheets/d/1SLUOmEz57aaPVL7kdH6uBhhKwSr1A1Oze3XjJJ-qaEU
Home Menu customization tutorial: https://3ds.codeberg.page/homemenu/ Home Menu customization documentation: https://docs.google.com/spreadsheets/d/1Q-Im3P5zSqNi6zYqaXtyS138hCdcIJDY7WxRt_FWdrg
I may start a TiddlyWiki..
Please recommend me any alternative places, tools, etc..
Currently working on a GNU/Linux variant of HMRT: https://github.com/schrmh/HMRT