* Improve English [#4161](https://github.com/FreshRSS/FreshRSS/pull/4161)
* Misc.
* Increase PHPStan to [level 5](https://phpstan.org/user-guide/rule-levels) for code quality, also fixing several PHP 8.1 warnings [#4110](https://github.com/FreshRSS/FreshRSS/pull/4110), [#4123](https://github.com/FreshRSS/FreshRSS/pull/4123), [#4119](https://github.com/FreshRSS/FreshRSS/pull/4119)
* Increase PHPStan to [level 5](https://phpstan.org/user-guide/rule-levels) for code quality, also fixing several PHP 8.1 warnings [#4110](https://github.com/FreshRSS/FreshRSS/pull/4110), [#4123](https://github.com/FreshRSS/FreshRSS/pull/4123), [#4119](https://github.com/FreshRSS/FreshRSS/pull/4119), [#4182](https://github.com/FreshRSS/FreshRSS/pull/4182)
* Clean temporary files generated by automated tests [#4177](https://github.com/FreshRSS/FreshRSS/pull/4177)
* Add automated spell checking of the code using [typos](https://github.com/crate-ci/typos) [#4138](https://github.com/FreshRSS/FreshRSS/pull/4138), [#4134](https://github.com/FreshRSS/FreshRSS/pull/4134)
* Enforce code style *opening brace on same line* in PHPCS [#4122](https://github.com/FreshRSS/FreshRSS/pull/4122)