The Baselines Level 1 & Level 2 Test Suites report (ASIDE → Reports → Baselines Level 1 & Level 2 Test Suites) shows the SAVED baseline snapshots of a test plan: for every platform, one table per baseline capture with the First/Latest execution window and the "Baseline taken on" timestamp, listing Top : Child (L1 : L2) suite rows with per-status quantities/percentages and the completion percentage at capture time. It replaces the legacy 1.9.20 lib/results/baselinel1l2.php HTML view with a modern Dashio-styled page backed by a plain-PHP REST BFF.

Path: ASIDE menu → Reports → Baselines Level 1 & Level 2 Test Suites URL: gui/templates/results/baselineL1L2.html?tproject_id=<id>&tplan_id=<id> BFF API: api/reports/index.php — GET ?action=metrics_baseline_l1l2&tproject_id=&tplan_id= Rights: testplan_metrics Tracking issue: #673

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The header carries the test plan context; the teal "Important Notice" banner appears only when the plan has platforms (legacy platform-relationship counting rule). Each platform gets its own card titled "Results on Platform: <name>"; inside, EVERY saved baseline snapshot renders as its own block:

• Baseline taken on: <timestamp> – when the baseline was captured (newest first, legacy ORDER BY BLC.creation_ts DESC).
• First/Latest Execution on: – the execution window covered by the snapshot.
• The classic matrix:

Column	Content
Top : Child (Test Suites)	L1:L2 suite path, alphabetical order (legacy SQL top_name ASC, child_name ASC)
Total	test cases linked for that platform at capture time
Not Run / Passed / Failed / Blocked	qty + [%] per status (server-localized labels, results-config display order)
Completed [%]	(total - not_run) / total * 100 — same formula as legacy

• Send by email to myself – POSTs to the legacy baselinel1l2.php?format=<MAIL_HTML> flow.
• Export data as spreadsheet – downloads TestLink_GTMP_<proj>_<plan>.xls from the legacy XLS generator.
• Refresh – re-fetches the BFF metrics.

A plan without any saved baseline shows an explicit friendly message pointing to the Save baseline action on the Results by Test Suite report (the legacy page simply rendered nothing).

Unchanged from legacy: open Results by Test Suite (resultsByTSuite.php) and use its Save baseline action — it writes one baseline_l1l2_context row (+baseline_l1l2_details) per platform. The modern screen reads exactly those tables; you can capture several snapshots over time and compare them side by side.

GET /api/reports/index.php?action=metrics_baseline_l1l2&tproject_id=<id>&tplan_id=<id>

Key payload fields: hasData, show_platforms, platform_blocks (ordered [{id,name,snapshots:[{begin,end,baseline_ts,rows:[…]}]}] — real arrays so JS cannot re-sort platform/snapshot order), columns (status label map in display order), plus legacy send_mail_url / export_xls_url. Timestamps are raw and formatted client-side (the server strftime path renders placeholders literally under PHP 8, see #563).

Permission handling mirrors legacy checkRights(): no session ⇒ 401; missing testplan_metrics on global role AND project context ⇒ 403 (users holding the right only via a per-project role pass, like hasRightOnProj()).

18 bll.* keys in all 10 locale bundles (en de es fr it ja pt ro ru zh); bll.header mirrors the legacy page title baseline_l1l2.

13-case regression matrix (Suite 673) in tmp/TLU_Test_Cases.md: BFF parity vs DB, multi-snapshot ordering, empty state, XLS/mail exports, 403 path, aside switch, refresh, locale switcher, i18n completeness, Event Viewer clean.