The Set Syntax (Emacs) package fork of Lee Dohm's 'Set Syntax' package, specified for Emacs syntax.
This package was created for use as a command in the atom-console package.
As within the original package, there are no key bindings set by default, though you could set keys for specific languages that you use often. For example:
This package is available as open source under the terms of the MIT License.
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.