The php setup is used in places where only an Apache server is available and no docker environment can be deployed. The php backend replaces what otherwise would have been taken care of by the backend. Have a look at the preferred backend option to know more about the functioning as this php backend tries to imitate that as close as possible.
Additionally, instead of serving the frontend using an nginx container, the apache server also provides the frontend as static files.
To build the PHP setup, use the build scripts /src/build.sh to compile it into a zip.
bash build.shFor a top-level domain setup.
bash build-SARSCov2.shFor the setup where the app lives under the path /SARSCov2/. This also uses the special environment.SARSCov2.ts in the frontend.
The technology used for this php backend is PHP running on Apache.