4th video looking at Joomla 4 concepts relating to upgrading components from Joomla 3. Slides at https://docs.google.com/presentation/d/1-Dc4Nkn5fAyt3TYxSAWB0KYN49-UDJRKNTnChpK-D-s/edit?usp=sharing
The references quoted in the video are:
https://www.youtube.com/watch?v=igx3bIl1T_c
https://www.youtube.com/watch?v=78Vpg97rQwE
https://docs.joomla.org/J4.x:Dependency_Injection_in_Joomla_4
https://www.php-fig.org/psr/psr-11/
https://stackoverflow.com/a/30547499
https://stackoverflow.com/questions/7417430/javascript-closures-vs-php-closures-whats-the-difference
https://www.dionysopoulos.me/book/concepts-container.html
