Before you start: depend on Core

Every X-Lifestyle mod declares Core as a required dependency in its own .meta:

requiredMods:
  - name: "X-Lifestyle Core"
    loadMyMod: after

loadMyMod: after means your mod loads after Core, so window.BMFT is already populated by the time your own scripts run. This is a real, engine-enforced field (xcl-core's mod-order resolver reads it to build load-order relationships), not just documentation — see your mod's own .meta schema reference for the full field shape if you need a version constraint too.