Select only required routine columns (possible fix for bug #3515776)
Add anchors to database and table sections to allow linking
Allow using lang() in plugin with single language Adminer version
Allow using lang() in plugins
Save memory in get_file()
Remove bzip2 compression support

It didn't work for exports bigger than 1 MB.
An alternative would be to remove the limit from output buffer which would need memory for the whole export.
Another alternative would be to create a temporary file in output handler and bzwrite() to this file - that would work but it's complicated, especially if we want to output the file progressively - bzopen($tmp, 'w'), fopen($tmp, 'r').
Export SQLite views
Allow exporting views dependent on each other (bug #3459151)
Reduce memory used by TAR export
Display logout button in Nette design.