Plasma LookNFeel packages can contain and apply Latte Layouts. Distros and designers can include their latte layouts inside their own Plasma LookNFeel package and Plasma will auto adjust everything in order to load or unload the latte layout. In case the looknfeel package does not contain any latte layout then we can guess that Latte is not needed and for that reason is closed. You can of course restart Latte afterwards if you want to.
Latte Dock >= 0.10.6
Plasma Desktop >= 5.24.0
Go to Plasma SystemSettings → Appearance → Global Theme
Install your Plasma LookNFeel package
Check option "Use desktop layout from theme"
Apply it in your system.
For Designers / Distros
Export your latte layout through: Right click Dock → Layouts → Edit Layouts... → Choose your favorite layout → Export → Export As Template...
Rename the exported layout file to : looknfeel.layout.latte
Include your looknfeel.layout.latte file inside the layouts folder of your looknfeel package