I've seen BTC used interchangeably with XBT when looking at cryptocurrency exchanges. What does XBT stand for, and why is it used? 

XBT is another code used to represent Bitcoin, similar to BTC, which is the more commonly used code. The use of XBT primarily stems from the conventions used in the traditional financial system, where currency codes are typically derived from the International Standard for currency codes (ISO 4217). ISO currency codes typically consist of a country code (first two letters) followed by the first letter of the currency name. Since Bitcoin is not tied to any country, it does not easily fit into this structure. However, 'X' is used for international currencies and precious metals, like gold (XAU) and silver (XAG), leading to the use of XBT for Bitcoin. For a detailed explanation of why XBT is used, how it differs from BTC, and what it means for investors and traders, this article is a valuable resource: https://paybis.com/blog/glossary/xbt/ It explores the origin and usage of the XBT code in the context of Bitcoin and financial markets.