There is only one file type that uses the .LASSO extension:
Lasso Database-Driven Web Page
Dynamic Web page that may include Lasso (LDML) code; can access database information using Lasso commands; may be integrated into websites created with Dreamweaver or GoLive, or built from scratch using Lasso Professional.
Lasso is commonly used to publish FileMaker Pro (.FP5, .FP7, etc.) databases, but can be used with Access, 4D, Oracle, MySQL, and SQL Server databases as well.
Updated: September 19, 2012