An update… I was looking in the wrong editor. But now that I found the SITES keyword in the right editor, I still did not manage to do it. There are so many lines of code with SITES, and I was unable to find one that is related to the tab named SITES.
After that, I used LiveJasmin as a keyword. I found it in a few locations, and I changed it with the name of my whitelabel. But it still displayed the name LiveJasmin on the SITES tab.