Kelp, press K for help in neovim. Reclaim our K binding. (Noadays K is mapped to some LSP function.) Kelp does what keywordprg do but with more nobs.

Installation (lazy.nvim)

return {
 "https://codeberg.org/nzeo/kelp",
 version = "*",
 lazy = false,
 opts = {
 kelpprg = "",
 keyword = "<cexpr>",
 filetype = "",
 only = false,
 },
}