Eh, the PHP pitfalls that I'll never learn by heart... Thanks! :)
Let's try if ($file !== null && $file !== '') instead of if ($file) then?

Restore an empty line

This broken code is intended to find MailTags (means: each entry listed under http://phorge.localhost/settings/panel/emailpreferences/ , grep for const MAILTAG_ to get a list of them) defined more than once to display them in a Common section on top:

Before:

Fix $Mailer default value in docs

• Between class.phpmailer-lite.php and class.phpmailer.php there were two differences in default values of variables, for $Mailer and $SingleTo:
  • I kept Lite's public $SingleTo = true as src/applications/metamta/adapter/PhabricatorMailSMTPAdapter.php (using non-Lite) already explicitly sets $smtp->SingleTo = false.
  • I kept Lite's public $Mailer = 'mail' instead of non-Lite's public $Mailer = 'sendmail' as SMTP in non-Lite already explicitly sets $Mailer = 'smtp' via calling $smtp->IsSMTP(), same for Sendmail via $mailer->IsSendmail(), and custom AmazonSES's code already explicitly sets $mailer->Mailer = 'amazon-ses' in src/applications/metamta/adapter/PhabricatorMailAmazonSESAdapter.php - so our default value sendmail does not really matter here anyway.
• The other PhabricatorMail*Adapter subclasses of PhabricatorMailAdapter do not seem to utilize PHPMailer.
• No documentation to update as https://we.phorge.it/book/phorge/article/configuring_outbound_email/ does not mention any PHPMailer.

In https://we.phorge.it/source/phorge/browse/master/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php ,
getMailAction() does return $this->getStrongestAction($object, $xactions)->getActionName()
and
getStrongestAction() does return head(msortv($xactions, 'newActionStrengthSortVector'))
and
newActionStrengthSortVector() does return id(new PhutilSortVector())->addInt(-$this->getActionStrength()) (note the minus)
so I'm wondering if rPf4d9d6920bcdcafedd6a05f34c28642589b3c285 broke something while it was supposed to do the opposite (cannot remember another recent commit that feels related to this area).

Remove unused final protected methods in PhabricatorEditorExtension

But it's designed to accept an array of futures, not a single one. Maybe just wrap in array($result).

Remove unused save() method in PhabricatorUserCache

In D25645#19609, @valerio.bozzolan wrote:

It would be nice to understand why nothing calls save() 🤔 since I guess nothing calls it, or we would have a crash report.

or am I supposed to $result = id(new ArcanistHardpointFutureList())->newFromFutures($result);? Yeez

Screenshots of {desktop, tablet, phone} width, exposing an arrow only on tablet and phone as we previously made people scroll large distances anyway and to increase discoverability of the feature in these viewports:

Apply phone style also to tablet style because same rendering (only one column)

Set cursor: pointer in CSS

Sigh, xdebug... and seems I need to drop the new from the constructor when the class is final.

Per https://caniuse.com/?search=-webkit-transform, transform without a vendor prefix has been supported since Chrome 36 in 2014.
Personally I'd prefer to simply remove old vendor prefixed CSS definitions but that would first require a shared understanding which dates (and/or which browser versions) are "too old" for Phorge code.
See "List of changes, most recent first" on https://www.mediawiki.org/wiki/Compatibility#Browser_support_matrix for a random example.

A day later this turns out to be a rather stupid patch. Things should remain as is as javascript:void(0) nowadays may trigger CSP errors.