Unfortunately, the Lab Browser can not be installed as a native extension on Apple's Safari browser.
Here's how you can still use it, by setting the Lab Browser as your Homepage in Safari.
STEP 1Safari > Preferences
STEP 2Under General, in the dropdown menu "New Tabs open with", select the value "Homepage".
STEP 3In the field "Homepage", enter the website "https://my.labbrowser.com".
Done!That's all. Enjoy the Lab Browser on Safari.