I hear that they don’t embed tracking metadata in those builds on the FTP, but I haven’t confirmed that.
The normal download page embeds a unique tracking alphanumeric string in your build that is reported to the organization on a regular basis when the telemetry phones home unless you disable this manually and clear the values.
I believe it was getfirefox.com, which I remember primarily from adding banners to websites I ran back in the day. I forgot who previously owned firefox.com but I recall them adding a link to getfirefox.com on it back in the day.