User Experience Librarian is more about outside of the library walls

The position (with many variants, including: emerging technology librarian' embedded librarian; Electronic Access and User Experience Librarian, Public Services-User Experience Librarian III / Instructor in the Library; Assessment and User Experience Librarian, USER EXPERIENCE REFERENCE LIBRARIAN AND WEBMASTER; Digital User Experience Librarian);  is more about analytics (metrics) and user experiences, than librarianship in any traditional sense of the term.

Examples of the job descriptions are here:

• Knowledge and understanding of best practices, current issues and trends in assessment and usability [job ad at University of Manitoba Libraries]
• Knowledge of metadata coding standards. Experience with library catalogue end users and/or end users of electronic resources... Website design and maintenance experience. [job ad at Nova Scotia Provincial Library]
• basic knowledge ofMARC; experience with one or more Library enterprise systems suchas library management systems (Symphony, Aleph, Endeavor),discovery interfaces (Ebsco Discovery Services, Summon, Primo),search technologies (Solr, Elasticsearch), course managementsoftware (Sakai, Canvas, BlackBoard) [job ad for Discovery User Experience Librarian at Indiana University ]
• will coordinate usability assessment for the library, including designing and carrying out usability studies, analyzing usage statistics and user trends to support planning and development, and advising on the user-centered design requirements and recommending solutions for other departments and stakeholders. This position will also work with the Communications Coordinator to provide oversight of changes and new content for the library website via a content management system (CMS). Additional responsibilities will include working to build and manage the libraries’ social media presence; advising and recommending on web standards, styles, and accessibility guidelines; and actively exploring and making recommendations for best practices with current web technologies. [job ad at Texas at San Antonio Library]
• As User Experience Librarian, this person works closely with the individuals responsible for digital initiatives and online access to the Libraries' resources to produce a seamless online library experience; evaluates the Libraries' website by undertaking usability studies and analyzing usage of the website; collaborates with library faculty and staff to integrate appropriate technologies into the Libraries' online environment to improve library services and instruction; and monitors trends related to the web and library technologies. As the Libraries' webmaster, the person is responsible for developing and maintaining the Libraries' website in accordance with university standards. [job ad at UNIVERSITY OF NORTHERN COLORADO]
• Serves as a member of the Technical Services Team and is responsible for the successful management of access to electronic resources in the Library’s collections
  o Provide leadership in access management of OpenURL link resolvers (Serial Solutions), ERMS, A-Z title lists, troubleshooting access problems and user support
  o Provide training and support for library staff related to electronic access
  o Participate in LibGuides administration and library discovery tool (Summon) management
  • Serves on a cross departmental team to explore ways to enhance the user experience throughout the library
  o Participate in library wide assessment activities
  o Promote electronic resource usage to campus community in collaboration with other library groups
  • Leads a team that oversees tracking and management of usage statistics of electronic resources
  • Participates on license review team; identifies key license terms and enter license terms into ERM software [ad at Minnesota State University]
• ... daily operation and maintenance of the Nova Scotia Digital Media collection, optimising OPAC functionality, and focusing on other IT-related projects that will improve patrons' library experiences [roles at Nova Scotia Provincial Library]
• will serve as a member of the Libraries Assessment and Web Teams; collect, analyze, and communicate assessment data; interact with user communities to identify their priorities and needs; help improve the Libraries’ program for gathering, archiving, and analyzing statistics and survey data; coordinate usability studies for the Libraries’ web sites [job ad at The University of Dayton]
• Experience with HTML/web authoring and editing programs
  • Experience using Sirsi ILS modules.
  • Experience using focus groups, surveys and similar usability
  methodologies.
  • Experience assessing student learning. [jo ad  at The Richard E. Bjork Library at the Richard Stockton College of New Jersey]

On the same shelf:

• PEC Kit 322: Library User Experience   Robert Fox
• Embedded Librarianship: What Every Academic Librarian Should Know   Alice L. Daugherty
• Working in the Virtual Stacks: The New Library and Information Science   Laura Townsend Kane
• Using Web Analytics in the Library (Library Technology Reports)   Kate Marek
• E-metrics for Library and Information Professionals: How to Use Data for Managing and Evaluating Electronic Resource Collections   Andrew C. White
• Viewing Library Metrics from Different Perspectives: Inputs, Outputs, and Outcomes   Robert E. Dugan
• Conducting Action Research to Evaluate Your School Library
  Judith A. Sykes
• Web Metrics for Library and Information Professionals   David Stuart
• Analyzing Library Collection Use With Excel
  Tony Greiner
• Library Analytics and Metrics: Using Data to Drive Decisions and Services   Ben Showers
• Developing Benchmarking Metrics: a Librarian's Guide (Library Benchmarking Noteb
  Holly J. Muir