I have the same issue with Talend Open Studio 7.1.1
Lots of great extensions that my jobs would need, but all of them just give a brief popup window indicating that download starts but then nothing happens, no component show up.
Are you able to see them in downloaded extensions with install button right to that?
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Introduction to Talend Open Studio for Data Integration.
Practical steps to developing your data integration strategy.
Create systems and workflow to manage clean data ingestion and data transformation.