call expression in firefox.cfg

Firefox is used on Windows 11 Enterprise. There is a firefox.cfg in the installation directory (and an autoconfig.js in the ./defaults/pref sub-directory). Everything works fine when a pref(...); entry is written to the firefox.cfg. However, we want the firefox.cfg to call the pref(...); entries from a global_config.js which is saved on the machines public directory. Therefore, the firefox.cfg says: // free line lockPref("autoadmin.global_config_url","file:///C:/Users/Public/.../global_config.js"); But firefox does not load whatever prefs are written to the global_config.js. There probably is problems with the formatting of the file path (file:///C:/Users/Public/.../global_config.js). What would the correct formatting look like? Unfortunately, Mozilla´s support guide only includes an example code for a firefox.cfg which calls a global_config.js via http:, but not via file:.