I don’t think everything uses some kind of premade file index. Whenever I start up everything, it starts with indexing all my drives, one by one, churning them at 100% if I look at the task manager but everything even says so in the bottom left corner. it even stores hundreds of megabytes of that index in memory.

what it actually does, as I know, is that instead of going through the slower filesystem APIs, it first scans the MFT with its admin rights, and then listens for any changes through the usn journal. so it does quite some work, because afaik both of these are publicly undocumented, and then it even implenents a very quick search for the index that even supports pattern matching