One or two posts on this site imply that the Brave project has indeed included the code for the Chrome task manager in its codebase. But that doesn’t appear to actually be the case in the compiled executables coming down the pike, AFAIK (and it’s well-hidden at best, if it is included).
A per tab/process task manager for the Brave browser is frankly crucial for keeping control of browser operations in many instances. Security or otherwise.
Shipping a – prominent, easy-to-access – Brave task manager should be some sort of priority, IMHO.