This plugin allows for quickly swapping between header and source files. It is intended to be used for languages like C or C++. It might work for other languages having a similar structure too, since you can specify custom patterns to swap between files.
With the default swap patterns
let g:swapc_patterns = [
\ [ '#{prefix}/src/#{sub}/${file}.?{cc,c,cpp,cxx,C}',
\ '#{prefix}/include/#{sub}/${file}.?{hh,h,hpp,hxx,H}' ] ]
one can switch between files
some/prefix/src/some/folders/file.h
some/prefix/include/some/folders/file.c
using shortcut <Leader>6
.