With Filestar you get 0 different skills for working productively with FastTracker II Extended Instrument (.xi) files.
About .Xi
Name
FastTracker II Extended Instrument
Extension
.xi
Format
Binary
Category
Audio
Developer
Triton
Description
A FastTracker II Extended Instrument (.xi) stores one tracker instrument: envelopes, a keyboard map and up to 16 delta-coded 8 or 16-bit mono samples, as written by FastTracker II, MilkyTracker and OpenMPT.