Go to unmatched '[' and ']'

The same as what [{ and ]} does for { and }, except for [ and ].

Customization

Use g:gotobracket_nomap to disable the default [r and ]r mappings.
E.g.,

let g:gotobracket_nomap = 1

Use <Plug>GotoOpenBracket and <Plug>GotoCloseBracket to define your own mappings.
E.g.,

nmap <silent><Leader>[ <Plug>GotoOpenBracket
nmap <silent><Leader>] <Plug>GotoCloseBracket
xmap <silent><Leader>[ <Plug>GotoOpenBracket
xmap <silent><Leader>] <Plug>GotoCloseBracket
omap <silent><Leader>[ <Plug>GotoOpenBracket
omap <silent><Leader>] <Plug>GotoCloseBracket