This is the "Tab ID". It is not sent over the network as I understand and is only available from the local js context. It's the result of a bit of hackery Chrom

This is the "Tab ID". It is not sent over the network as I understand and is only available from the local js context. It's the result of a bit of hackery Chrome does to map requests to the webview. EDIT: Found the bug report... https://code.google.com/p/chromium/issues/detail?id=355541 https://code.google.com/p/chromium/issues/detail?id=355541