Update: Based on the discussion here and in other places I added the following (well, technically I did something different in my colorscheme, but in the end it translates to that)
vim.api.nvim_set_hl(0, 'Normal', {})
This reverts the weird text and background colors to the previous behavior of ... not setting them.
With update 0.10 Neovim behavior changed regarding text color and background color.
I use a color theme that does not set those and previously this worked perfectly fine. Neovim simply used the font color defined in the terminal and had a transparent background.
Now the background is #14161b and the font color is #e0e2ea. Neither of the colors is configured ANYWHERE in my whole setup. Neither in the colorscheme, nor in my terminal configuration, nor in my Neovim configuration.
Is there a sane way to revert this to the old behavior? (i.e. use the font color configured in the terminal’s configuration and use transparent background.)
So I need to disable all the non-treesitter definitions first?
Do you know if there is a way to completely disable the built-in styling?
I have treesitter as well and didn't do anything specific before adding these lines to my config. If you're looking to change "everything" without tweaking each highlight parameter individually you may be interested in this plugin.
I don’t want to make Neovim transparent, though. I have an own colorschme and just don’t want the default colorscheme to be applied.