I have heard of neither. But the mention of Burrows leads me to Burrows-Wheeler, which is a compression algorithm (bzip).

I'm not 100% but I don't think you can directly query a BWT in the same way you'd query an inverted index (without the later discovery of wavelet trees and FM-indexes / succinct data structures, and all that jazz.) And that's mostly for genomics? Not sure if it applies to plain old document searches. Would love to be corrected though.

At Meta they are using FM indexes to power text search through the entire commit history of their monorepo.