Adding your own skill lines (Build 42.x)

require "API/DST_API"

Use one of:
DST.SkillTooltips.addStaticLevels("Carpentry", { [1] = {"..."} })
DST.SkillTooltips.addLevelLines("Carpentry", 2, "Line A", "Line B")
DST.SkillTooltips.addSimpleComputed("Carpentry", function(level) return {"..."} end)
DST.SkillTooltips.register({ skill="Carpentry", static={...}, compute=function(level) ... end })

Use display names (“Carpentry”, “Foraging”, “Electrical”). Internal IDs like Woodwork are auto-mapped.
Put text in translations when possible (IGUI_DST_*) to support localization.

(See _Template.lua.template for full example)