{#- The brand at the header's left: the mark beside the wordmark, linked to the site's home page, the landing page at `rietx_home` (WP-2021). The top-left logo of a site's subsite goes to the site's home; the way back to this manual's own front page is the breadcrumb's first item, "Manual", on every page but that one (`breadcrumbs.html`). The mark is inline SVG filled from `--accent`, never an ``: an embedded SVG is its own document, cannot see `html[data-theme]`, and so would follow the system theme and ignore the toggle (the old manual's `sidebar/brand.html` had the measurement, mask-image included). Its shapes are a copy of the site's favicon, `docs/landing/src/favicon.svg`, which `tests/test_manual.py` pins. `rietx_name` is `_about.DIST_NAME`, handed over through `html_context`. -#}