Is mapleader not supported in vim-tiny? #19617

I've used vim-tiny (default Vim 9.1 version bundled on Debian and Ubuntu) on a couple of occasions and I was surprised that <leader> mappings don't work at all.

I cannot set mapleader using legacy Vimscript (e.g., let mapleader = "," or let g:mapleader = ",") because the +eval feature is missing, so the let statement is not available. Changing the leader with Vim9script syntax (g:mapleader = ",") doesn't throw an error, but it doesn't seem to have any effect either. This is documented, so no surprises here.

I can create leader mappings (e.g., nnoremap <leader>b <cmd>buffers<CR>), and I can see that they are configured correctly (:nmap <leader>b prints the correct mapping), but I cannot trigger them, neither with the custom leader (e.g., ,), nor with the default \, which is documented to be used as a fallback in case g:mapleader is empty or not set.

Since there's no way to change g:mapleader without +eval, leaving it empty, I would have expected Vim to fallback on the default \ leader, and for the leader mappings to work.

My questions:

1. Are leader mappings not supported at all in vim-tiny?
2. Since leader mappings are so ubiquitous, would it be feasible to support them even without the +eval feature, at least with the default \ leader?
3. Building on top of the previous request, would it be feasible to provide some way of configuring a custom mapleader without the +eval feature?

Thanks!