Source: https://www.zaproxy.org/docs/desktop/addons/neonmarker/

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Neonmarker

Neonmarker add-on, which colours History table entries based on tags.

The add-on also facilitates colouring arbitrary messages in the History table via a right-click context menu. Tags are added to the selected messages to deliver the necessary colouring. Neonmarker’s custom tags take the form neon_UUID , for example: neon_e8b1d1e6-9dd4-4996-bc02-de2213986352 . Another context menu item provides functionality to remove Neonmarker’s custom tags.

The following code example shows how to add a Neonmarker colorMapping via JavaScript within ZAP using a Stand Alone script.

		extNeon = control.getExtensionLoader().getExtension(org.zaproxy.zap.extension.neonmarker.ExtensionNeonmarker.NAME);
		
		// History items tagged “Comment” will be red
		extNeon.addColorMapping("Comment", 0x990000);