"BRchan" does not refer to any specific concept or topic that I'm aware of. It's possible that the term has emerged or evolved since then, so I'm unable to provide a specific answer without more context.
However, I can explain ADHD hyperfocus in general terms. Hyperfocus is a common phenomenon experienced by some individuals with Attention Deficit Hyperactivity Disorder (ADHD). It refers to an intense state of concentration and absorption in a particular task or activity. During hyperfocus, people with ADHD can become so engrossed in what they are doing that they lose track of time and may neglect other responsibilities or tasks.
Hyperfocus can occur on a wide range of topics or activities, depending on an individual's interests and personal preferences. It might involve tasks related to work, hobbies, video games, art, reading, or even internet communities and forums. So, if "BRchan" is a topic, community, or activity that someone with ADHD finds particularly engaging or stimulating, it's possible for them to experience hyperfocus in that context.