https://www.playframework.com/documentation/2.5.x/Anatomy

'project/project' is valid directory for 'project' project-related files. For example, if one configure his sbt build to use scala files directly from 'project/', dependencies like 'project/project/plugins.sbt' will be ignored because of this line.
See http://www.scala-sbt.org/0.13/tutorial/Organizing-Build.html#sbt+is+recursive.

The *.iml file is IDE specific.  It is generated by Intellij IDEA to store project related metadata.  It is not a Play Framework specific artifact and should not be included in the PlayFramework.gitignore.

See: https://github.com/github/gitignore/pull/1581

I would also vote for the removal of .eclipse and *.eml files on similar grounds but will do so in a separate pull request.

The original ignore was far too general and results in eliminating packages
named "db" or "project", for example. These are not that uncommon for package
names. Fixes #921.

Link: http://www.playframework.com/documentation/2.2.x/Anatomy

Because files and directories starting with a `.` are not ignored in general.

as stated in the official documentation http://www.playframework.org/documentation/2.0/Anatomy

Added 'lib' and 'modules' folders which should also be excluded, since libs are automatically fetched from dependencies.yml.
Also removed duplicate 'elicpse' entry.

Adds modules. It is used to keep the full path of each module required by the application. It can be generated using: '$ play dependencies --sync'

Conflicts:

	PlayFramework.gitignore