Off-line documentation is included with the product.

Changelog:

Blendit v1.1

Implemented full support of Frame Nodes
Fixed issue with Reroute Node and full support of these nodes
Fixed issues caused by incompatibility with other add-ons affect material nodes

Blendit v1.2

Automatic linking of unconnected node mapping input
Basic warning if unsupported mapping is used
Basic warning if unsupported nodes are used
Fixed blended material doesn't work in Cycles
Fixed transfer of active UV Map instead of UV Map with Active Render

Blendit v1.3

Full support of material nodes (ColorRamp, RGB Curve, Vector Curves)
Small performance improvement through better modifiers settings
Auto Smooth option added to Settings (recommended to turn-off in Cycles)
Added switches for Simple and Advanced blend modes
Advanced mode - added option to tweak the minimum blend distance
Advanced mode - added option to tweak the gradient of the material blend
Advanced mode - added option to tweak the blend of normals
Fixed issue and added warning if objects have no materials
Fixed Transfer UV doesn't have ideal mapping when Blend Normals disabled
Fixed Auto smooth did not return when blend was removed
Fixed UV Map node could have non-existent UVs assigned
Fixed applied blend shows sliders without influence

Blendit v1.4

Added Blend Styles: Noise dithering, Height map blending, Custom map dithering
Added Preview Modes for blends: By gradient and By gradient with thresholds
Added Show / Hide blend switcher
Added UV Mapping Scale option for non transferred UV mapping
Blendit modifiers have closed details by default
When blend is created or Blend Style is changed, source init values are used
Added warning icon for enabled Blend Normals setting when it should be disabled
The add-on no longer disappear when an unsupported object is selected
Renamed Distance to Max Distance for consistency
Improved UI states of enabled / disabled buttons
Fixed wrong behavior when material linked to object / data was used
Fixed and improved parenting inside Frame nodes, broken in v1.3
Fixed wrong mapping when non-image texture nodes use default mapping
Fixed issue when materials have multiple output nodes or wrong output setup
Fixed not appearing of Material Warning in specific case
Fixed availability of the Individual Scale parameter for non blended objects
Fixed issue with removing blends on objects Excluded from View Layer