# Force a trailing slash on all virtual requests (except WP admin area).
<IfModule rewrite_module>
  RewriteEngine On
  RewriteBase %%REWRITE_BASE%%

  # If not a real file or directory.
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d

  # Not a part of the WP admin area.
  RewriteCond %{REQUEST_URI} !(?:^|/)wp\-admin(?:/|$)

  # Not a REST request, which never redirects.
  RewriteCond %{REQUEST_URI} !(?:^|/)%%REST_REQUEST_PREFIX_AS_REGEX_FRAG%%(?:/|$)

  # If there is no trailing slash.
  RewriteCond %{REQUEST_URI} !/$

  # Force a trailing slash on all virtual requests.
  RewriteRule ^(.*)$ $1/ [QSA,L,R=301]
</IfModule>