tracklang package FAQ
The purpose of tracklang is to provide a common interface to query the document localisation information. This is described in more detail in Localisation with tracklang.tex.
The problem is described in Localisation with tracklang.tex. (Basically, babel doesn’t currently provide a convenient way for another package to detect if
\babelprovide has been used.)
No. Its purpose is simply to provide a framework to help packages detect which document languages have been specified.