Why? Please provide a user story / good reasons, as "because we can" is not a great argument when it comes to the costs of maintaining additional code in the next years. Thanks. :)

I want to have time on czech Wikipedia in format "hh:mm, dd. month yyyy". But there are only possibilities for

hh.mm, dd. month yyyy
hh:mm, dd.mm.yyyy

the time and date format I want is the most used in Czech Republic, but czech Wikipedia community doesn't care. They are used to use the second short format and the long format is not popular because of that dot.

I assume T125204: Add some another $dateFormats possibilities to MessagesCs.php is where the wind blows from?

Yes, that's the problem and this could be one of possible solutions.

Possible duplicate of T133285

@Dalba I guess you meant T3784: Add the ability to specify custom date formats in Special:Preferences. ;-)

Yeah, thanks @Danny_B!

Also, T63409 will be resolved if this task is resolved, but I don't know if it's appropriate to merge it to this task or not as it is requesting for only a specific case (T-less ISO-style).

Why were T3784, T14280, and T63409 merged into this much newer task?

It looks like T94610 and T133285 should also be merged into T3784.

In T133285#2441355, @MZMcBride wrote:

Why were T3784, T14280, and T63409 merged into this much newer task?

Because this one contains biggest discussion (and those were obviously laid forgotten).

In T133285#2441362, @MZMcBride wrote:

It looks like T94610 and T133285 should also be merged into T3784.

I think T94610: Date format option should have "other" text field for date format strings shouldn't have been closed as duplicate, but rather added as a subtask of this one.

In T133285#2441380, @Danny_B wrote:

In T133285#2441355, @MZMcBride wrote:

Why were T3784, T14280, and T63409 merged into this much newer task?

Because this one contains biggest discussion (and those were obviously laid forgotten).

Forgotten? They're mentioned in this task. I think we remembered them.

Any valuable discussion here can be copied to the older task. I personally don't see any comments worth copying over.

In T133285#2441362, @MZMcBride wrote:

It looks like T94610 and T133285 should also be merged into T3784.

I think T94610: Date format option should have "other" text field for date format strings shouldn't have been closed as duplicate, but rather added as a subtask of this one.

I don't see how T94610 would be a subtask of T3784.

In T133285#2441404, @MZMcBride wrote:

In T133285#2441380, @Danny_B wrote:

In T133285#2441355, @MZMcBride wrote:

Why were T3784, T14280, and T63409 merged into this much newer task?

Because this one contains biggest discussion (and those were obviously laid forgotten).

Forgotten? They're mentioned in this task. I think we remembered them.

Mentioned? Merged into as a part of dupe-hunt maintenance...

Any valuable discussion here can be copied to the older task. I personally don't see any comments worth copying over.

In T133285#2441362, @MZMcBride wrote:

It looks like T94610 and T133285 should also be merged into T3784.

I think T94610: Date format option should have "other" text field for date format strings shouldn't have been closed as duplicate, but rather added as a subtask of this one.

I don't see how T94610 would be a subtask of T3784.

I said "of this one"... If you allow custom formats, then you need a field.

In T133285#2441423, @Danny_B wrote:

Mentioned? Merged into as a part of dupe-hunt maintenance...

Mentioned. In comments such as T133285#2440863 and T133285#2440870.

I said "of this one"... If you allow custom formats, then you need a field.

Of this one refers to T133285, which appears to be a duplicate of T3784, as they are both requesting the same feature. That's why I mentioned T3784.

How would you "add the ability to specify custom date formats in Special:Preferences" without also resolving T94610? Maybe I'm misunderstanding what T94610 is about, but in my mind, any implementation of this feature request would make that task moot/resolved.