In gyp days, we used handwritten .isolate files to control what gets uploaded to swarming (they were compiled to ".isolated" files). Nowadays, mb/gn generates .isolated files directly, so in theory we shouldn't need all these .isolate files anymore.
I'll try to delete them. Shout if you think we still need them.
Comment 1 by thakis@chromium.org
, Mar 21 2017