About the Adjustment panel
The Adjustment panel presents color and tonal adjustments under adjustment type (e.g., HSL) as a series of preset thumbnails.
Selecting an adjustment type expands the view to show adjustment thumbnails, with each thumbnail applying an adjustment intended for specific uses (e.g., Desaturate); clicking on a thumbnail applies that preset.
The adjustment is added as an adjustment layer to your layer stack.
As you apply a preset you can fine-tune the preset's settings, optionally creating the modified adjustment as a new preset.