It folds into a penknife and is used to split rope into strands, so you can splice them.

Source: https://www.theguardian.com/lifeandstyle/2023/apr/29/i-cant-track-him-down-to-return-his-family-album-the-things-our-exes-left-behind-that-we-cant-bear-to-get-rid-of

The printed blocks and wedges, supplied by the USAF Rapid Sustainment Office, provide internal support to the C-5 hump panel covering a wing splice, as described by Clay Elliott, a C-5 structural engineering subject matter expert with the C-5 SPO.

Source: https://www.dvidshub.net/news/439421/3d-printed-parts-c-5m-deliver-new-capabilities