The interoperability allows the journal's contents to be collected by other distributors. Eclética Química uses the OAI-PMH Protocol from OJS, which can be accessed with the link:
https://revista.iq.unesp.br/ojs/index.php/ecletica/oai
The journal's meta tags are accessed by right-clicking on any page of the journal's website and choosing View Page Source.
The articles have tags meta which can be seen by just right-clicking on an EPUB article page and choosing "View page source" and you can see it.