We’re in the process of updating the documentation for Zotero 5.0. Some documentation may be outdated in the meantime. Thanks for your understanding.
Translator priority determines which order the translators are called for detect* and do* stages of translation. The lower the priority value the earlier the translator is called.
The priority for a web translator should be chosen according to the following guidelines:
(see https://github.com/aurimasv/translators/commit/5b4ef451a9c3c14fa9b2b8d5bce37a8bf7c1a3f2 for more information)
Higher priority (lower value) translators will override translators for detectWeb even in other frames of the web page window and will become the translator invoked by the URL bar icon.
The priority for import translators is mostly important for automatic detection of translators when importing metadata from files. The first translator that matches in detectImport stage will be used for import. Generally, different metadata formats will not match against different translators, but where this is a possibility, the translator priority may be important.
Priority is important to consider for search translators, where several translators may match against given metadata. In this case, lower priority value should be assigned to translators that have more broadly applicable databases (e.g. Library of Congress vs Lulu for ISBN, or CrossRef vs mEDRA for DOI) and preferably to APIs with fast response times.
Priorities are not relevant to export translators.