[question] What are descriptors?

[yeahlol]

After some searching I still need some help to wrap my head around "descriptors". What are they?

I found some outdated stuff here for pulling health:

uint DescriptorOffset = 0x08;
Descriptor = Memory.ReadUInt(ObjectPointer + DescriptorOffset);
int health = Memory.ReadInt(Descriptor + (0x17 * 4))

What i dont understand, is the descriptor offset 0x08 for all? Thats silly because you could then just add 0x08 to all addresses. But here is a thought, is the descriptor a variable field that changes patch to patch? (now im just throwing out theorys, dont want to get flamed for wanted to get spoonfed here...)

And could anyone explain why i need to use descriptor to pull health? Reading the offset from playerbase works just as fine and to top it all: could i get a expample to how i read player name (do you have to use descriptors, because ive had some problems reading it from

playerName = 0x8B3FB0