The tweet refers to research from 2012 where escape characters can act as no-ops to bypass WAF or filters. This technique can be used in XSS attacks to evade web application firewalls and filtering mechanisms. The tweet provides links to the research. It is important for security researchers and developers to be aware of such bypass techniques to enhance the security of web applications.
For more insights, check out the original tweet here: https://twitter.com/joaxcar/status/1813323757831811472