On May 24, 2025, nvim-treesitter announced that the master branch has been archived in favor of the main branch. fnl/conjure/tree-sitter.fnl tries to load the ts_utils module . It no longer exists in the main branch.
From the Neovim version 0.11 help on treesitter, one doesn't need to use the nvim-treesitter plugin because additional parsers can be manually installed when needed. So, I'm not sure how big an issue this is or if I'm totally clueless.