Abbreviations like S1, BX2 and IBL on a listing describe how a line was made, and they tell you a lot about how uniform the plants will be. An S1 is a self pollinated clone, a backcross narrows toward one parent, and an inbred line has been stabilised over many generations. There is a glossary on https://budweedseeds.com that explains each code in a sentence or two, which saved me looking them up one by one. More stable lines cost more, so know what you are paying for.