Fallout 76 is still using the same Creation Engine used to power Skyrim and Fallout 4. It even uses the same assets from Fallout 4. There are no two ways to go about it. People know it and Bethesda knows that people know.
Twitter user Christian Leites discovered engine code in Fallout 76 that was taken directly from Fallout 4 and Skyrim. It can be clearly seen that the Fallout 76 code directly references and uses lines from Fallout 4 and Skyrim codes. While it’s easy to understand that since all games use the same engine, it’s easier to copy-paste codes from one to the other to fasten development. But the least they could have done is to pretty up the code a little bit.
However, this one clearly indicates the sloppiness of Bethesda. Bethesda has also used the exact scripts and animations for dragons of Skyrim the Scorchbeast Queen in Fallout 76. Explains why they’re so similar, doesn’t it?
Bethesda should hope that modders don’t dig too deep and uncover secrets they doesn’t want us to know.