I'm not Neovim person, but would you happen to know what plugin provides that feature?

Sorry I'm exhausted and lazy.nvim is the package manager, but I meant lazyvim which is the distribution. Within this distribution I'm pretty sure it's which-key that provides a popup. If I type <leader> it pops with suggestion (and a little icon in front of each indicating if the next key has sub-commands or not).

folke/which-key.nvim: https://github.com/folke/which-key.nvim :

> Customizable Layouts: choose from classic, modern, and helix presets or customize the window.

LazyVim keymaps: https://www.lazyvim.org/keymaps