How do I write the html for [VC_raw_html]?

I am currently making changes to the page made by someone else.
The previous developer wrote something like below:

[vc_raw_html]JTNDY2VudGVyJTNFJTNDYSUyMGhyZWYlM0QlMjJodHRwcyUzQSUyRiUyRnd3dy5jbXItYXNzb2NpYXRlcy5jb20lMkZhdXRvLWluc3VyYW5jZSUyRiUyMiUzRSUzQ2ltZyUyMHNyYyUzRCUyMmh0dHBzJTNBJTJGJTJGd3d3LmNtci1hc3NvY2lhdGVzLmNvbSUyRndwLWNvbnRlbnQlMkZ1cGxvYWRzJTJGMjAxOCUyRjA0JTJGY29ycmVjdGF1dG8uanBnJTIyJTIwJTNFJTNDJTJGYSUzRSUzQyUyRmNlbnRlciUzRSUwQSUzQ2NlbnRlciUzRSUzQ2g0JTNFQXV0byUzQyUyRmg0JTNFJTNDJTJGY2VudGVyJTNF[/vc_raw_html]

Between the two bracket [vc_raw_html] and [/vc_raw_html], what is that thing? It doesn’t look like HTML at all. How can I generate some code like that?