What is the 50a6 rule in Texas?

Excuse me, could you possibly clarify what the "50a6 rule" refers to in the context of Texas? I'm not familiar with this particular term, and I'm curious to know if it's a legal regulation, a financial guideline, or perhaps something related to cryptocurrency or finance. Could you elaborate on its purpose, significance, and any potential impact it might have on residents or businesses in the state of Texas? Thank you for your time and consideration.