Hi @GNPU,
That is a third-party-developed plugin. There is an original plugin developed here: GitHub - a-vodka/ojs_copernicus_export_plugin: Plug-in allows to export article meta-data to Copernicus citation index
But that has not been updated in some time.
And, there has is also a plugin discussed here in relation to 3.3: Index Copernicus export plugin for OJS3.3.0.8 - #8 by Surojit_Bera
But that plugin has since disappeared from Github.
I don’t think this plugin for 3.4 exists, so far as I know.
-Roger
PKP Team