This product contains a code plugin, complete with pre-built binaries and all its source code that integrates with Unreal Engine, which can be installed to an engine version of your choice then enabled on a per-project basis.
VaTexAtlas is the plugin for Unreal Engine 4 that makes texture atlases simpler to use with UMG system.
The plugin is designed to work with sprite sheet data exported from TexturePacker using JSON Array data format.
VaTexAtlas is completely free and available under MIT open-source license. You can use it in commercial projects, you can modify anything, etc. In other words, you're in charge.