What to learn in php?

Question

PHP

Hello. I am a full stack web developer. It so happened that I started with other languages, so when I switched to the web, I immediately took up frameworks and best practices, skipping the stage of pure php. Played with it for two years and got used to it. But I'm afraid that when I get to an interview at an IT company in my city, they will ask me questions about php syntax; nuances usually hidden behind a framework/library; optimization issues, too, are usually hidden.
If I had a free choice there, this question would not be here. I know and use all new technologies. It's all old and hidden)
Question: what kind of literature to read?

Answer 1

php.net is the largest literature that can be found in one place.
And so I will say from personal experience, go through several interviews and you will find out what they require and what knowledge and learn them a little.
BUT!
Most importantly, you must understand what you are doing and simply must be able to find solutions to various tasks.
Good luck!