Can you provide some testing instructions?

I tried here an article with diverse email addresses and for some reason cloaking does not work for those with unicode (e.g. Russian kyrillic) characters, regardless if both name and domain or only the domain contains such chars.

I don't think it is related to this pull request (PR).

But to be sure, testing instructions would help.

I will test as soon as I have some instructions and find time.

Beside this, could you close the issue #13741 ?

As soon as there is a PR for an issue, the issue can be closed, but since you did not tell in this PR here that is it for that issue, it may take a while until someone notices that and closes the issue.

In general, if you already have a solution for an issue, you do not need to make an issue and a PR separately, instead of this you can do just the PR, this includes also the issue report. Just in case if you don't know that yet.

#13741 in the issue of changing the other file. I did not understand how to combine the two files in the same issue, so did 2.

I see

What is the testing instructions?
The list of possible e-mail addresses?

No, it's just a description on how to test this pull request, see other pull requests for examples.

Testing Instructions

Status Quo

Open Users. 
Press the New button.
Try to insert into the field "Email" UTF-8 the address (a user name @ a server name) for example: Вадим@Ригин.рф
The field "Email" will be noted red.
After attempt of preservation of the user the system will give the message "Invalid field: Email"

Change
After application of this PR

Open Users. 
Press the New button.
Try to insert into the field "Email" UTF-8 the address (a user name @ a server name) for example:
The field "Email" will remain normal.
After preservation of the user the system will give the message on its preservation.

Possible addresses in the UTF-8 format:

Вадим@Ригин.рф
Вадим-Ригин@почта.рф
Вадим.Ригин@почта.рф
Вадим_Ригин@почта.рф

I have tested this item ? unsuccessfully on 6fc3d8d

Email-Field Вадим@Ригин.рф stay after PR red an user isn't saved as without PR.

As far as I remember, Joomla uses a regex which does not deal with non ascii characters in the local part.
See https://github.com/joomla/joomla-cms/blob/staging/media/system/js/validate-uncompressed.js#L212 (and in validate.js)

In any case, a mail of type Вадим@Ригин.рф will not be cloaked by Joomla while a mail of type joomla@Ригин.рф will as the domain part is punyencoded.
See the regex here:
https://github.com/joomla/joomla-cms/blob/staging/plugins/content/emailcloak/emailcloak.php#L119

Yes, exactly, Joomla is now not misses the UTF-8 characters in a local part of the address, and that's not right - they are valid.
I'm doing the store, and can come any client with any e-mail.

According to Jean Marie (infograf768), this PR here and the other one #13770 should be closed.

thanks @richard67

@franz-wohlkoenig This should be closed per @infograf768 @richard67

Set to "closed" on behalf of @franz-wohlkoenig by The JTracker Application at issues.joomla.org/joomla-cms/13742

closed as stated above.

Thanks for Hint @Quy