Import feature? Reload option? Namespace of NameMapping? I'm not sure what you're referencing. What I see on your screenshot is that the CU_LaunchLogin keyword test is shared with another project. So, I'm assuming you used the Add -> Existing item to add that keyword test to project B.
And yes, the "importing" references the imported test... FILE... So, there's a file on your drive called CU_LaunchLogin.tcKDT. When you did "add existing item", it linked that file to the new project. Renaming the file will break that link. If you change the file contents in one project, the update is automatic to the other.
Here's some hints:
1) Think of each "project" in TestComplete as if it is an application being developed in an IDE.
2) Each keyword test is a unit of code in that application
3) As in an application, if you change a unit of code in one application, all applications that use that same unit of code are automatically updated.
4) If you delete, remove, rename, or otherwise alter the file identification of the unit of code, that will "break" all those other applications unless you go to them and make the same updates
5) NameMapping, while not quite like a unit of code, follows the same rules. It is a file that, by default, "belongs" to a project. So, each project has it's own NameMapping file. As mentioned above, you can share the NameMapping between projects either by having them share the same file directly OR by manually merging the files as necessary.
Again, please look into getting into the basic TestComplete 101 training. These are basic concepts to TestComplete covered in the training and in the documentation.