Activation shows errors in console

[rugk]

When I start Firefox in the console and activate this add-on some errors are shown:

1475670927789   [email protected]  WARN    Loading extension '[email protected]': Reading manifest: Error processing background.persistent: Event pages are not currently supported. This will run as a persistent background page.
1475670927791   [email protected]  WARN    Loading extension '[email protected]': Reading manifest: Error processing author: An unexpected property was found in the WebExtension manifest.
1475670927791   [email protected]  WARN    Loading extension '[email protected]': Reading manifest: Error processing minimum_chrome_version: An unexpected property was found in the WebExtension manifest.
1475670927791   [email protected]  WARN    Loading extension '[email protected]': Reading manifest: Error processing minimum_edge_version: An unexpected property was found in the WebExtension manifest.
1475670927850   [email protected]  WARN    Please specify whether you want browser_style or not in your browser_action options.

These errors are also shown on subsequent starts.

Firefox 49.0
Linux x64

[ericlaw1979]

The manifest errors are all a result of the fact that the code is the same between Firefox and Chrome.