I suddenly remembered I have a Doogee S40 Lite somewhere in a large box. Unlike the usual devices I tinker with, this one is Android-based, MT6580.  The IMEI editor code there is `*#*#8688#*#*`. Does it make it more privacy-friendly? Heck no. Doogee is notorious for inserting firmware-based trojans/adware in the past, so I still am looking for some alternative ROMs for that one.