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Newer versions of GLPI contain the item name in the browser tab name now. For tickets, the subject would be exposed publicly.

While interesting, would this not expose information to unauthenticated users unless only generic data is used?

The title would have to always be just "GLPI" and there is no generic description that would fit everyone's needs.

There is a native English (American) speaker on the GLPI development team as of 2020 and we have been fixing some of the little discrepancies in the default en_GB text in GLPI itself and plugins, translated the user documentation to English, and more.

Yes. As far as I can tell, this has existed since at least 0.85.

Partially implemented.

When creating a child location or child-entity, it will copy the geolocation data from the parent item if it exists. This doesn't affect locations or entities which are already created though.

Added in GLPI 10.0

Done for GLPI 10.0 with the Pending Reasons feature.

When adding a followup, you can set a pending reason template which will handle automatic "bumping" of the ticket and close the ticket automatically after a predetermined number of "bumps" without any response from the user.

Both points have been addressed in GLPI 10.

1. The filters are now in a popover accessible from a single button at the bottom of the ticket view

2. Another button was added next to the filters button to display all TODO tasks in a checklist type of view

This is already in the latest release of GLPI. I do not know which version it was added in.