Is there anyway to reset just the navigation

[산도]

I installed nodebb-plugin-header-extend plugin and then wanted to go back to default navigation.
After going back to default navigation, I was able to see some small blank icons in the navigation , so I activated the plugin again and deleted all the icons.
Then all the icons were gone, and I was not able to put back any navigation icons into it. Is there anyway to make it default? like resetting just the navigation part?