Developer tooling. Fires one ESPN read at a time and prints exactly what came back, so a page is only ever built on fields that really exist.
Prefilled from the connection strip above, and only used by this page — checking here does not change what the rest of the site is connected to, so you can point a probe at another league or an older season safely. A private league needs the Fantasy Football Bridge extension installed and enabled; without it only leagues marked viewable to the public will answer.
Confirms what ESPN actually returns, so we know what we can build on.