When you define a Map\URI matcher that contains umlauts, such as "flüchtlinge", and then try to access content on a frontend siteaccess (non-legacy), it fails, because the matcher's umlauts are replaced by underscores.

Example:

example.com/fl_chtlinge/myfolder/myarticle

Steps to reproduce:

1. Prepare a test installation of eZ Publish 5.4, updated to 5.4.6;
2. Create the following content structure:

Home
    MyFolder
        MyArticle

3. Modify ezpublish.yml:

ezpublish:
    siteaccess:
        ...
        match:
            Compound\LogicalAnd:
                my_compound_rule_1:
                    matchers:
                        Map\URI:
                            'flüchtlinge': true
                        Map\Host:
                            example.com: true
                    match: ezdemo_site

4. Accessing the following link will work:

http://example.com/flüchtlinge/MyFolder

5. However, when you access the "MyFolder" page and click on the "MyArticle" link, you will be re-directed to "http://example.com/fl_chtlinge/MyFolder/MyArticle", instead of "http://example.com/flüchtlinge/MyFolder/MyArticle", and a "Module not found" error will be displayed.

All links to contents directly under the root node are OK, but all contents under that level will have broken links if the siteaccess matcher has umlauts in it.

Note: although I'm accessing a siteaccess that is in non-legacy mode, the problem seems to originate in this legacy template:

/ezpublish_legacy/extension/ezdemo/design/ezdemo/override/templates/full/folder.tpl