Linux Releases

Option 1 - Flathub

flatpak install flathub com.obsproject.Studio.Plugin.DroidCam

Option 2 - Manual Install via zip file

The DroidCam plugin releases are made to be generic and mostly self contained. The main dependency is ffmpeg.

FFMpeg-4 - Ubuntu 22.04 Jammy (and lower)
FFMpeg-5 - Ubuntu 22.10 Kinetic
FFMpeg-6 - Ubuntu 23.10 Mantic / Flatpak

You may check which FFMpeg version your system is using, and download accordingly.
Specifically, it is the libavcodec package that matters:
libavcodec58 == ffmpeg-4
libavcodec59 == ffmpeg-5
libavcodec60 == ffmpeg-6

DroidCam OBS Plugin Releases

Consult the README.TXT in the download zip on how to install.