FileInfo.com - The File Extensions Resource

.MAB File Extension

File Type	Mozilla Address Book
File Format	File
Common?	No
File Description	Address book format used by Netscape and Mozilla mail programs; abook.mab = personal address book; history.mab = collected addresses; impab.mab = imported address book
Program(s) that open mab files	Mac / Windows: Netscape or Mozilla Web browser

Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/mab