How do you pick the prefixs

Don’t stress about it. What matters is picking something quickly, making sure everything uses the prefix in that folder and making sure it’s a smallish amount of code in the folder - a “small drawer”.

Why is this?

Because it’s easy to move the code around, rename it or eliminate it if the code is no longer needed.

All text editors make it easy to go global “Search and Replace” operations across an entire code base. In fact if you apply the prefix namespace concept to spreadsheets then spreadsheets also support the ability to search and replace unique names across the entire spreadsheet. Cool eh!