It is critical to avoid unofficial "mirror" sites which may package plugins with malware. The developer has officially archived legacy versions for users of older software. LibFredo6 - SketchUcation

LibFredo6 is a foundational shared library required for nearly all SketchUp extensions developed by , such as Curviloft , RoundCorner , and JointPushPull . While the latest version is optimized for modern SketchUp releases, many users actively seek a LibFredo6 old version to maintain compatibility with legacy software. Why You Might Need a LibFredo6 Old Version

These versions are no longer supported by modern LibFredo6 updates.

Older versions of the library are sometimes preferred for high-resolution screen adjustments in SketchUp 2016, where manual scaling (often a factor of 2) is required.