Manual:Plainlinks
The plainlinks class removes the little arrow that would normally show up with an external link.
The MediaWiki CSS class plainlinks is one of several built in classes. It can be used when constructing internal links to special pages that are not otherwise possible.
An example of the use of the plainlinks class within a template would be the following:
<span class="plainlinks">[{{ fullurl: Special:Allpages |namespace={{{1|3}}} }} {{ ns: {{{1|3}}} }}]</span>
Result: User talk
or simply
<span class="plainlinks">https://www.mediawiki.org/w/index.php?title=Special:Allpages&namespace=3</span>
Result: https://www.mediawiki.org/w/index.php?title=Special:Allpages&namespace=3
or even
<span class="plainlinks">[https://www.mediawiki.org/w/index.php?title=Special:Allpages&namespace=3 Link text]</span>
Result: Link text
You could also adjust the css file with the correct internal link color #002bb8. Change in "plainlinks a":
#bodyContent .plainlinks a {
background: none !important;
padding: 0 !important;
color: #002bb8 !important;
}