There are two ways of removing the powered by MediaWiki logo added at the footer of MediaWiki CMS website. You can also change the powered by MediaWiki text to something that you want.
Option 1: added the code below LocalSettings.php file
unset( $wgFooterIcons[‘poweredby’] );
Option 2: If option 1 does not work then add the following code to the LocalSettings.php file. Replace the "managed by us" message with your site name, resources/assets/poweredby_mediawiki_88x31.png with your logo, and blogiestools.com with your site url.
$wgFooterIcons = [
"copyright" => [
"copyright" => [], // placeholder for the built-in copyright icon
],
"poweredby" => [
"mediawiki" => [
// Defaults to point at
// "$wgResourceBasePath/resources/assets/poweredby_mediawiki_88x31.png"
// plus srcset for 1.5x, 2x resolution variants.
"src" => false,
"url" => "https://blogiestools.com",
"alt" => "Managed by us",
]
],
];