From the press release:
The Government Publishing Office (GPO) makes available a subset of enrolled bills, public and private laws, and the Statutes at Large in Beta United States Legislative Markup (USLM) XML, a format that makes documents easier to download and repurpose.
The documents available in the Beta USLM XML format include enrolled bills and public laws beginning with the 113th Congress (2013) and the Statutes at Large beginning with the 108th Congress (2003). They are available on govinfo, GPO’s one-stop site to authentic, published Government information. www.govinfo.gov/bulkdata
H/T Gary Price, InfoDocket