As a PHP Developer one should be aware of following
- What is PHP, what are the different versions available
- What is End of Life in Software industry
- How to use PHP
- Apache / NGINX / PHP-FPM
- Server Side / CLI / CRONs
- What is Code deprecation, how to stay updated about it
- Rector
- Keeping code quality in check
- PHPStan
- PHPCS
- PHPMD
- Different layers of Caching
- OPCache
- APCu
- MemCache / Redis / Database / File System
- Varnish
- CDN
- Tools to help debug / investigate
- XDEBUG
- XHPROF or other profiling tools
- Miscellaneous
- Composer
- Load Balancer
- Databases (MySQL / NoSQL like Mongo)
And most importantly, how to ask questions to Google (or even to other people)
