One of my first projects as a professional software engineer at the ripe age of 19 was customizing a pair of Google Search Appliances that my employer had bought. They'd shelled out hundreds of thousands of dollars to rack yellow-faced Dell servers running CentOS with some Google-y Python because they thought that being able to perform full-text searches of vast CIFS document stores would streamline their business development processes. Circa 2011 XHTML was all the rage and the GSA's modus operandi was to transform search results served from the backend in XML into XHTML via XSLT. I took the stock template and turned it into an unholy abomination that served something resembling the rest of the corporate intranet portal by way of assets and markup stolen from rendered Coldfusion application pages, StackOverflow, and W3Schools tutorials.
I learned quickly to leave this particular experience off of my resume as sundry DoD contractors contacted me on LinkedIn for my "XML expertise" to participate in various documentation modernization projects.
The next time you sigh as you use JSX to iterate over an array of Typescript interfaces deserialized from a JSON response remember this post - you could be me doing the same in XSLT :-).