The standard Scala XML library. Please file issues here instead of over at issues.scala-lang.org.
As of Scala 2.11, this library is a separate jar that can be omitted from Scala projects that do not use XML. If you are cross-building a project that uses scala-xml with Scala 2.10 and Scala 2.11, take a look this example.
The compiler was decoupled from this particular implementation using the same approach as for comprehensions (xml syntax is desugared into a set of method calls, which unfortunately is only defined by the implementation). Alternative implementations are welcome!
API documentation is available here.
This library is community-maintained. The lead maintainer is @biswanaths.
Security best practices
The XML spec has some features that are best turned off, to avoid unsavory things like file system access, DoS attacks,... Issue #17 tracks the recommended way of configuring the xml parser used by scala-xml to avoid these. This is by no means an exhaustive list. We'll be happy to incorporate your suggestions -- just comment on the ticket!