.XLA File Extension
File TypeExcel Add-In File
This file is saved in a binary format, which requires a specific program to read its contents.
What is an XLA file?
Adds modules, extra functions, and other tools to Microsoft Excel; may be included with the Excel software program, developed by a third-party, or created by the user.
Excel Add-In files can be created an added by selecting "Add-Ins..." from the Tools menu in Excel.