On testing both EZP-25490 and EZP-25580, there were no steps to install the ez-support-tools bundle, or any info whatsoever on the affected install.md file.
The steps performed at the time, provided by gunnstein.lye@ez.no, were as follows:

1. Get the bundle:

git clone git@github.com:ezsystems/ez-support-tools.git vendor/ezsystems/ez-support-tools

2. Register the bundle on app/AppKernel.php, by adding:

new EzSystems\EzSupportToolsBundle\EzSystemsEzSupportToolsBundle(),

to the bundles array;

3. Clear caches;

4. Add to composer.json the following psr-4 norm:

"autoload": {
	"psr-0": { "": "src/" },
	"psr-4": {
		"EzSystems\\EzSupportToolsBundle\\": "vendor/ezsystems/ez-support-tools/"
	}
},

5. Add to composer.json as well the following "require" norm:

"require": {
	(...),
	"ezsystems/ez-support-tools": "@dev"
},