@matmarex thanks for your opinion, about localisation issue; there is a manifest for localisations, this manifest will determine the language structure, for example if its RTL, etc.... I think this matter (space after/before/none) can be placed in this manifest.

In T249149#6020475, @Aklapper wrote:

Hi @armin.taghavizad, thanks for taking the time to report this and welcome to Wikimedia Phabricator!

I am not sure I understand. In the future, please follow https://www.mediawiki.org/wiki/How_to_report_a_bug - thanks! :)

I go to https://commons.wikimedia.org/wiki/File:Example.jpg and I do not see the word "Filename" anywhere on that page.
Do you maybe refer to the URL (web address) of the page, and the page title File:Example.jpg displayed on top of the page? That is intentional, as the page title is the same as the part of the URL. File: is the Namespace prefix, and that is an intentional technical implementation, though it might be confusing.

In T249149#6020457, @matmarex wrote:

I don't see the word "Filename" anywhere on file description pages. Can you clarify what you mean?

Do you mean the "File:" in the page title? For example on https://en.wikipedia.org/wiki/File:The_Fighting_Temeraire,_JMW_Turner,_National_Gallery.jpg: