systemd-resolved stub resolver and direct resolv.conf access

Fedora utilizes systemd-resolved as the primary DNS manager, operating a stub resolver at 127.0.0.53. While this manages per-link DNS routing and local caching, a behavioral discrepancy occurs when applications bypass the D-Bus interface to read /etc/resolv.conf directly.

The standard configuration relies on /etc/resolv.conf being a symlink to /run/systemd/resolve/stub-resolv.conf. However, if applications or specific container configurations expect a static file or a different path, they may fail to respect the DNS settings or domain-specific routing managed via resolvectl.

How does systemd-resolved ensure consistency when /etc/resolv.conf is not symlinked to the stub configuration? What are the specific indicators that an application is bypassing the stub resolver in favor of the system-wide trust or DNS settings?