I tried to start showing the preview package option and there is no FBX Exporter either
Try adding it by name?
package names are in their urls:
https://docs.unity3d.com/Packages/com.unity.formats.fbx@5.1/manual/installation.html
Here: com.unity.formats.fbx
But what I want to tell you is! 2020.3 doesn’t seem to have been added by name!

I don’t know if it’s the “genius” Unity China who did it, because I saw in some videos that normal unity2020 has FBX Exporter
What about a new, empty project? Is the package missing there as well?
You can manually add this to your project’s dependencies in Packages/manifest.json to check if it installs:
"com.unity.formats.fbx": "5.1.1",
Note: omit the comma at the end if you add it as the last line under “dependencies” in the json.
According to the package.json the minimum required version is 2020.3 and both dependent packages (Autodesk FBX, Timeline) also at most require 2020.3. So it should work, it may just not appear in the package manager for some reason (perhaps a mistake).
You might also want to upgrade to 2021.3 at least. In most cases such upgrades aren’t nearly as painful as our fear of upgrading makes us believe it is. Do note that even 2021.3 LTS is near the end of its support term with the release of Unity 6 LTS yesterday.
To be honest, I saw the FBX Exporter in normal Unity 2020.3.48f, and 2020.3.48f1c1 provided by Unity China doesn’t have this plugin! It’s really infuriating, and it’s not once or twice that they’ve done this kind of thing!
Unity may be legally obligated to do so!
For instance due to export restrictions or because Autodesk policies prohibiting the distribution of their FBX SDK in China for some reason (including the export restrictions).
This is not a problem, they provided Fbx exporter in a higher 2021.3, as you prompted, in 2020.3.48fc1, I can add Fbx exporter, the problem is solved, thank you very much! brothers


