The folder:

  //telemetry/telemetry/internal/bin

Does not include any checked in files but is used by the DependencyManager to download binary files into it.

So the folder has to be excluded from:
https://cs.chromium.org/chromium/src/tools/perf/chrome_telemetry_build/BUILD.gn?rcl=9ea9b5ee08b766efcf2ea8188f2444b52db93696&l=190

to prevent from copying files in it to isolate outputs.

This makes it awkward to maintain, since adding new files or folders to Telemetry (in catapult) require changes to that list before they can roll into chromium.

Instead, we should just move that path to:

  //telemetry/bin

Which would allow all of:

  //telemetry/telemetry/

to be included in the BUILD.gn rules.