These are for the combined vim-sexp (https://github.com/guns/vim-sexp) and vim-sexp-mappings-for-regular-people (https://github.com/tpope/vim-sexp-mappings-for-regular-people) plugins. vim-sexp is neat on its own but Tim Pope makes common stuff much easier.
Note that some vim-sexp functionality depends on <LocalLeader> mappings. This is a different leader key than the global leader, and is the variable maplocalleader (instead of mapleader). To see if you have this set, use :echo maplocalleader; if it errors out you'll need to set it, otherwise it will echo the key. If you want to set your LocalLeader to <Space>, you'll need two commands in your .vimrc, since by default <Space> is bound to <Right> in normal mode:
nnoremap <Space> <Nop>
let maplocalleader=" "