Version 6.3.3 from the Library of Congress - https://www.loc.gov/preservation/digital/formats/digformatsp...
Writeup on zip file Appnotes: https://entropymine.wordpress.com/2019/08/22/survey-of-zip-a...
Actual PKWare AppNotes: https://support.pkware.com/display/PKZIP/Application+Note+Ar...
Section 4.4.5 is "compression method"