Meta (Facebook’s parent company) employs automated hash-matching technology from (Microsoft) and Thorn to detect known CSAM. However, new variants of the video are uploaded constantly, and the text “el video de la niña” is not itself illegal. The phrase is generic enough that it also appears in legitimate news articles.
Claiming "I was just curious" will not protect you if the link contains illegal material. Your ISP (Internet Service Provider) logs every URL you visit. el video de la ni%C3%B1a de facebook link