Applets, extensions are installed at ~/.local/share/cinnamon/.
User configs are at ~/.cinnamon/.
Writing Extensions
How to make a Cinnamon theme : Cinnamon
How to make a Cinnamon applet (Force Quit applet tutorial) : Cinnamon
Cinnamon 1.8 settings API – some lesser-known bits ← Segfault
Applet, Desklet, Extension Settings API – a brief example. ← Segfault
Cinnamon 1.8 Applet, Desklet, Extension and Theme packaging guidelines ← Segfault
Cinnamon 1.8 Theme Notes ← Segfault
Nemo Actions
Behind the curtain.. Nemo actions ← Segfault
Write a .nemo_action file in
/usr/share/nemo/actions/~/.local/share/nemo/actions/
Nemo Actions - ArchWiki
nemo/files/usr/share/nemo/actions at master · linuxmint/nemo
[Solved: Github nemo patch available]:nemo actions: problem with single quotes in filenames? - Linux Mint Forums
smurphos/nemo_actions_and_cinnamon_scripts: A collection of custom context menu items for the Nemo file manager, along with some miscellaneous feature scripts intended for the Cinnamon desktop environment.
Nemo Scripts
Located at
/usr/share/nemo/scripts/~/.local/share/nemo/scripts/
Creating a new Nemo script - Linux Mint Forums
nemo scripts pack - Gnome-look.org
The Ultimate Nautilus/Nemo Scripts Pack - linux-apps.com