>>7730644>>7730647"Resident egyptologist" here:
Burial mask was a thing related to egyptian funeral ritual. Egyptians believed that after death human soul 'splits' into few parts. The most important are Ba and Ka - personality soul and body soul (it's complicated) and burial mask was supposed to help Ba to find it's Ka. Mummified bodies were protected by various spells and rites to protect them from unwanted evil spirits. Burial mask helped Ba to find his/her Ka. If Ba was unable to find Ka, or Ka has been destroyed, they couldnt get into afterlife and Ba was stuck in bird-like form forever. There was also Akh but let's ignore it now.
That's brief info, as I said, it's complicated but this should be enough. The rest
>>7730674 is correct as well.