This link might help you in understanding your question Tableau Public Frequently Asked Questions . I guess the names will be selected by the popular keywords.
That link shows how you create a permalink that sends people, who land on your Tableau Public profile, to your website or blog where you've embedded your viz.
But I'm still curious how Public generates the original URL. I see now that the "\Data" in my URL matches the name of my first dashboard so I think there's where that piece comes from. But I still can't figure out how it came up with the <nameofviz> as it's not a keyword I used anywhere in the workbook.
I thought it might be the name of the workbook, but that's not always the case. For example, the Public URL for this author's viz (Tableau Public) uses
"AmericasBiggestBandwidthHogs_4" as the <nameofviz>, but the actual name of the workbook you can download is called "America's Biggest Bandwidth Hogs."
I suspect somewhere Tableau is saving previous workbook names, or doing some versioning of some sort, to come up with the <nameofviz> element in the URL.
Just curious if you have found the reason or workaround to control the generated hyperlink somehow. Please share if you have found anything about this.