It's against the servlet spec, see https://github.com/jakartaee/servlet/blob/6.0.0-RELEASE/spec/src/main/asciidoc/servlet-spec-body.adoc#352-uri-path-canonicalization
See also https://stackoverflow.com/a/74395733
Used in PageTemplatesIT#templateProviderTitleEscaping with the following URL: http://localhost:8080/xwiki/bin/edit/XWiki/%7B%7Bhtml%7D%7D%3Cspan%3EHTML%3C%2Fspan%3E%7B%7B%2Fhtml%7D%7D?template=XWiki.TemplateProviderTemplate&parent=XWiki.TemplateProviderClass&title=%7B%7Bhtml%7D%7D%3Cspan%3EHTML%3C%2Fspan%3E%7B%7B%2Fhtml%7D%7D&form_token=7ReNHIExSZo84JE25vsxdg