ua: <string>, // identifier derived from the user agent downloading the installer, e.g., chrome, Google Chrome 123
dltoken: <string>, // Unique token created at Firefox download time. ex: c18f86a3-f228-4d98-91bb-f90135c0aa9c
msstoresignedin: <boolean>, // optional, only present if the installation was done through the Microsoft Store, and was able to retrieve the "campaign ID" it was first installed with. this value is "true" if the user was signed into the Microsoft Store when they first installed, and false otherwise
dlsource: <string>, // identifier that indicate where installations of Firefox originate