New graphic effects for Godot
Discovering
I didn't know, that visible light sources is possible with lightmap.
After reading this Godot PR (it was not merged yet at the time of writing, hope for Godot 4.6 merge 🙏) I started waiting to merge... As like Area Light PR and now-merged SSAO for GLESv3 PR.
I waited some time... and knew, that I should make custom Godot build!
Building troubles.
At first, I merged SSAO PR to my fork of 4.5.1. But because lightmap specular PR was not merged yet, it was problematic to import these PR into my fork.
I solved that problem, using Git. I cloned original PR repo, squashed commits and made a patch, then applied patch to my fork.
Godot 4.5.1 custom build troubles.
I tried using compiled build, but backface culling (which was used in SCP: Containment Procedures) became glitched.
I narrowed down the issue - SSAO feature was buggy.
I made a custom build without SSAO - only with lightmap specular PR - no bugs were observed.
That's how was made SCP:Containment Procedures 5.4.0

Linux port
Since I have Windows 11 on my PC, I installed WSL to compile Godot template. After compiling finished, I made Linux port for SCP: Containment Procedures 5.4.1.
Stability?
GitHub CI from Godot Engine reported me, that my Godot build is unstable (althrough it was working on my PC and Android tablet)
I eventually decided, that SCP: Containment Procedures 5.4.2 will be latest version, used with that custom build. 5.3.x will be continued to be developed.