A simple Calibre metadata source plugin that uses the getMetadata service from http:https://xisbn.worldcat.org

• Searching is by ISBN only
• The returned metadata is limited to book title, authors, publisher, language and year (not the precise date)
• Other xISBN services like getEditions or searching the whole worldcat database are not supported
• The free publicly-accessible version of xISBN is limited to 1000 requests per day and the plugin does not have support for the subscription authentication