From the project website (accessed 2019-07-01):
The Homer and the Papyri database archived here was created in 2002 by Michael Jones, with the cooperation and supervision of the Stoa Consortium, edited at that time by Anne Mahoney and Ross Scaife. The database is now more than a decade old and has not been updated since 2003. Instead, complete editions of Homeric papyri are now being published as part of the Homer Multitext project. What follows is an overview of the current functionality of the two major types of searches available in this archived version of Homer and the Papyri.
Searching for variants: Users may search for variants by specifying Iliad or Odyssey, book number, or a particular witness, as described on the Homer and the Papyri Help page and in the Introduction. Searching and generating lists of papyrus witnesses: Lists of Homeric papyri (regardless of whether or not they contain variants) can be generated by the database for the Iliad and Odyssey by simply choosing the title and selecting the "search witnesses" button. This list cannot be further specified.