WBU meaning (https://saferloop.com/what-does-wbu-mean/), is a slang abbreviation of the early texting and instant messaging days when users were trying to save time and character by shortening phrases. It is the miniature of What About You? - a term employed to make the conversation two-way. With the raise of online chatting, using such platforms as MSN Messenger, Snapchat, or TikTok, such abbreviations as WBU, LOL, or BRB became the common digital lingo. WBU is nowadays one of the most popular and informal, yet friendly methods by which teens converse with each other online.
Source: Saferloop (https://saferloop.com/)