nvim-lspconfig/lua/lspconfig/configs/jinja_lsp.lua

-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
-- This config is DEPRECATED.
-- Use the configs in `lsp/` instead (requires Nvim 0.11).
--
-- ALL configs in `lua/lspconfig/configs/` will be DELETED.
-- They exist only to support Nvim 0.10 or older.
-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
return {
  default_config = {
    name = 'jinja_lsp',
    cmd = { 'jinja-lsp' },
    filetypes = { 'jinja' },
    root_dir = function(fname)
      return vim.fs.dirname(vim.fs.find('.git', { path = fname, upward = true })[1])
    end,
    single_file_support = true,
  },
  docs = {
    description = [[
jinja-lsp enhances minijinja development experience by providing Helix/Nvim users with advanced features such as autocomplete, syntax highlighting, hover, goto definition, code actions and linting.

The file types are not detected automatically, you can register them manually (see below) or override the filetypes:

```lua
vim.filetype.add {
  extension = {
    jinja = 'jinja',
    jinja2 = 'jinja',
    j2 = 'jinja',
  },
}
```
]],
  },
}