"Pretty Home Page" is not found in official PHP history. But I saw several people call PHP that way on the internet, and even in some books, teaching & publications:
An Experimental Study of Detecting and Correlating Different Intrusions | SANS Institute:
Php5: The Pretty Home Page Scripting Language
Intrusion Detection Systems with Snort: Advanced IDS Techniques Using Snort ...:
ACID useds PHP (Pretty Home Page) scripting language,
Security in Cyber-Physical Systems: Foundations and Applications:
components such as Apache, Pretty Home Page (PHP),
CS212 Web Programming - Final Exam Notes:
Originally Pretty Home Page Tools
Introduzione a PHP (at PHP Day 2003):
Storia del PHP : Rasmus Lerdorf e «Pretty Home Page»
Programmation avancée pour le Web:
PHP : "Pretty Home Page" inventé par Rasmus Lerdorf en 1994
20 years Pretty Home Pages - fortrabbit blog:
20 years Pretty Home Pages
Examples of Quality Documentation in Computing Industry:
Although Pretty Home Page is another criminal hack of the unix lineage,
Besser PHP programmieren (in a comment on Amazon):
PHP, das stand einmal für "Pretty Home Page" und dieser Name suggerierte irgendwie etwas hobbymäßiges. Später wurde dies in "PHP Hypertext Processor" umgewidmet und sollte andeuten, dass sich die Sprache professionalisiere.
(Translation: PHP, that once stood for "Pretty Home Page" and this name somehow suggested something hobby-like. Later, this was repurposed to "PHP Hypertext Processor" and was intended to indicate that the language was professionalizing.)
PHP string comparison with no quotes - Stack Overflow:
It's a legacy from the times when PHP were just a "Pretty home page" form interpreter and strongly discouraged nowadays.
Was "Pretty Home Page" just a funny nickname of PHP? Or was it once PHP's real name?
Someone has already asked this question in another forum, but received no conclusive answers: OFF-TOPIC Original PHP acronym
I looked at revision history of the Wikipedia page on PHP, but there are too many revisions. There's a tool called WikiBlame to find addition/removal, but I didn't find anything with it.