Import-Export add-on for old UnrealED .T3D files.
This requires at least Blender 3.3 LTS.
Download the latest release.
Blender: Edit > Preferences > Add-ons > Install...
In the open file dialog, select the archive and press "Install Add-on".
Blender will automatically fill the filter, otherwise the addon should appear in the list as "Import-Export: Import and export old Unreal .T3D format".
The add-on adds the following menu items:
File > Import > Import Unreal .T3D (.t3d)
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File > Export > Export Unreal .T3D (.t3d)
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Object > Export T3D to clipboard
to paste directly selected mesh(es) into the clipboard.