I mean, there are LXR and OpenGrok indexes of the various kernels... E.g., http://src.illumos.org/source/ http://src.illumos.org/source/ https://elixir.bootlin

I mean, there are LXR and OpenGrok indexes of the various kernels... E.g., http://src.illumos.org/source/ http://src.illumos.org/source/ https://elixir.bootlin.com/linux/latest/source https://elixir.bootlin.com/linux/latest/source etc... If you make a local clone, then cscope is great.