You can find more information about SAI (Software Application Index) files in the Data Flow Management Guide for UCMDB (Chapter 18). According to that document, "The Software Application Index (.zsai) files contain a database of software applications. The XML Enricher uses these files to perform application recognition."
Master.zsai Contains English versions of software and language-neutral versions of Windows software.
French.zsai Contains French versions of Windows software.
German.zsai Contains German versions of Windows software.
Unix.zsai Contains English and language-neutral versions of UNIX software.
BaseUnixOS.zsai Contains language-neutral installed package rules for base UNIX operating system software.
Mac.zsai Contains language-neurtral versions of Apple Mac software.
Legacy.zsai Contains older versions of Unix and Windows applications for all languages.