Board Thread:New Members Welcome Area/@comment-2600:1702:3D0:9EE0:7C85:47E0:A100:A0C4-20180811164941/@comment-3234315-20180811173832

It's an "expansion" for a warrior's strength: only fighters, barbarians, paladins and rangers get this, and it further modifies some of their stats as damage or carry weight. You find the values on the linked strength article.

Oh, and you don't get it with a "17" in front, only with "18". ;)