Grafana-8.3.1- Needed the usage of property external_manage_info in JS File

How to configure ‘external_manage_info’ property from grafana.ini file into the Homepage JS file ?
I am not aware of JS scripting.
I need to have environment name(names like DEV or QA or PROD) as AppTitle and LoginSubTitle. It will be great to have the piece of Code to embed in the 7095.fab5d6bbd438adca1160.js file
Or if my approach is wrong, Please correct me.