An internal methodology memo for the '新疆省口项目' (Xinjiang provincial-gateway project) and '联通IDC项目' (Unicom IDC project) states both rely on 现有的系统（TSG与CN） (the existing TSG and CN [CyberNarrator] systems) to Block/Monitor/identify mainstream apps, and describes a largely manual signature-engineering workflow -- download the target app, capture traffic with 科莱(Colasoft Capsa)/Wireshark, extract fingerprint fields (http.host, http.user_agent, quic.sni, ssl.handshake.extensions_server_name) by hand, and register a per-app signature -- extending CyberNarrator's documented role beyond Psiphon-IP-harvesting/Pakistan subscriber correlation into general domestic app-blocking alongside TSG.

Root-caused an Ethiopia SNI-block-failure incident to the detection mechanism itself: APP_SKETCH's FQDN-scanning module -- which exists specifically to identify Psiphon3 and Freegate via top-N SNI matching -- was CPU-expensive enough to saturate cores, triggering sapp's fail-open DDoS bypass and letting some target connections through uninspected. A signature-structure fix roughly doubled throughput (33K/s to 73K/s new connections) and disabling the fail-open bypass restored reliable blocking.

Across dozens of individual signature-rule JSON files in this batch, at least 40 distinct named commercial VPN products carry dedicated detection signatures (by IP src/dst, FQDN, JA3 hash, or protocol-specific payload): BeePassVPN, BetternetVPN (separate isakmp/ja3/WireGuard sub- signatures), BigMamaVPN, BravePrivateVPN, ExpressVPN (JA3 + UDP-payload variants), FlyVPN, hidemevpn (OpenVPN UDP payload), JourneyVPN, JumpjumpVPN, LetsVPN (JA3), Psiphon3 ("psiphon3vpn_serverip"), QuarkVPN, SecureVPN, SuperUnlimitedVPN, TurboVPN, VPNHero, VPNTurkey, and others, each dated/versioned (e.g. "_20240812") indicating an ongoing signature-maintenance pipeline rather than a one-off ruleset.

Live TSG session logs from an internal test/QA gateway (device_id 9800165603191146 / 21426003, data_center label XXG-TSG-BJ) show real sessions from named commercial VPN apps — AlohaBrowserLite, BeePassVPN, BravePrivateVPN (WireGuard), Proton VPN, Turbo VPN, CyberGhost, BetternetVPN, SuperUnlimitedVPN, TrustzoneVPN and VPNHero — each matched to a dedicated per-app security rule (e.g. Deny_Brave, Deny_BeePassvpn, deny_Super Unlimited VPN) and given security_action=Deny. One row's app_transition field records a layered classification chain 'Psiphon Provider' -> ... -> 'BravePrivateVPN' for a single session, indicating the engine attempts nested/tunnel-in-tunnel protocol identification, not just single-label app ID.

TSG's app-traffic classification relies on an updatable "App Sketch DB" component (uploaded as a versioned file to each deployment). A version bump at the Xinjiang Unicom province-exit + IDC site increased identified application-traffic share from 23% to 68% of total traffic within days, with ByteDance-attributed traffic alone rising from ~100TB/day to ~500TB/day identified, illustrating both the scale of traffic under classification and that classification itself is a frequently-updated, centrally-distributed database rather than a static build-time artifact.

Side-by-side internal performance comparison across Xinjiang (China Mobile carrier deployment, hostname cmcc-xj-server1-sapp-244), Fujian (domestic), and Ethiopia (E21) explicitly references the same 'app_sketch_maat' diagnostic log format at all three sites, confirming the identical AppSketch app-fingerprinting stack is used for domestic Xinjiang surveillance and for the exported Ethiopia deployment.

MESA_Platform's "quic" module (built and packaged as stellar-on-sapp/sapp RPMs) implements SNI/User-Agent extraction from both cleartext GQUIC (versions 23-59) and encrypted IETF QUIC RFC9000 ClientHello payloads, and supports a QUIC SNI whitelist -- i.e. the DPI pipeline decrypts/parses encrypted QUIC handshakes to recover the destination domain rather than being blocked by QUIC's encryption.