Watched Introducing JIMU Robot Mythical Series: UnicornBot Kit from YouTube
Introducing the JIMU Robot Mythical Series: UnicornBot Kit.
The instructions for the Jimu Unicorn robot don’t describe what the white pen-like thing, part T01 x 1 (WHT), is used for. The videos online don’t have it either.

Essentially it’s a building tool that can be pulled apart and the thin pointy end is for pushing the connectors out of their positions while the other end can be squeezed lightly like a tweezer to remove the connector pieces if they’re stuck.