With the wide introduction of sightly into AEM development it became more and more useful to mount a Filesystem into a local AEM instance.
Now you can edit sightly and other files in your favorite IDE and see the changes in AEM without the need of a deployment.
On the sling website you can find and download1 the FileSystem Provider which brings this functionality.
You can install it in the Felix console and need to configure the local path and the webapp root in crx.
Since version 2.0.4 of the Maven Sling plugin2 you can leave the configuration to maven:
This will upload the bundle and create the proper configuration to map your project paths.