/bikeshed-conversion

name: bikeshed-conversion
description: Guidelines for converting W3C specs to Bikeshed format. Covers anchor ID preservation, dfn handling, and common pitfalls. Read this before any Bikeshed conversion or migration work.

Bikeshed Conversion

Preserving Anchor IDs

When converting a spec to Bikeshed, **anchor IDs used by other specifications must be preserved**. Bikeshed auto-generates IDs for `<dfn>` elements based on their text content, but these auto-generated IDs often differ from the IDs that were in the original spec. Other specs link to these IDs, so changing them silently breaks cross-spec references.

The Problem

Bikeshed generates IDs like `dfn-wall-clock` from `<dfn>wall clock</dfn>`, but the original spec may have used a different ID or no explicit ID (relying on the HTML spec's own ID generation). When other W3C specs reference anchors like `#dfn-wall-clock`, `#dom-performance`, or `#dfn-coarsen-time`, those links break if the IDs change.

The Fix

Always add explicit `id` attributes to `<dfn>` elements to preserve the anchors other specs depend on:

<!-- BAD: Bikeshed auto-generates an ID that may differ from the original -->
<dfn data-export>wall clock</dfn>

<!-- GOOD: Explicit ID preserves the anchor -->
<dfn data-export id=dfn-wall-clock>wall clock</dfn>

Common ID Patterns to Preserve

Based on [w3c/hr-time#173](https://github.com/w3c/hr-time/pull/173), these are typical ID patterns that get lost:

| Type | Pattern | Example | |------|---------|---------| | Concept definitions | `dfn-{name}` | `id=dfn-wall-clock`, `id=dfn-monotonic-clock`, `id=dfn-duration` | | Algorithm definitions | `dfn-{algorithm-name}` | `id=dfn-coarsen-time`, `id=dfn-duration-from` | | IDL typedefs | `dom-{typename}` | `id=dom-domhighrestimestamp`, `id=dom-epochtimestamp` | | IDL interfaces | `dom-{interface}` | `id=dom-performance` | | IDL blocks | `idl-def-{name}` | `id=idl-def-domhighrestimestamp` | | Compound concepts | `dfn-{hyphenated}` | `id=dfn-current-high-resolution-time`, `id=dfn-relative-high-resolution-coarse-time` |

IDL Attribute Definitions

When converting `<dfn>` elements inside a `<dl>` that describes IDL interface attributes, add the `attribute` keyword to each `<dfn>` so Bikeshed knows they define IDL attributes (not plain terms). The parent `<dl>` should have `dfn-for` set to the interface name.

<!-- BAD: Bikeshed treats these as plain concept dfns -->
<dl dfn-for="PerformanceEntry" data-export>
  <dt><dfn>duration</dfn></dt>
  <dd>...</dd>
</dl>

<!-- GOOD: Bikeshed knows these are IDL attributes -->
<dl dfn-for="PerformanceEntry" data-export>
  <dt><dfn attribute>duration</dfn></dt>
  <dd>...</dd>
</dl>

Without the `attribute` keyword, Bikeshed won't correctly associate the dfn with the IDL attribute, and cross-references like `{{PerformanceEntry/duration}}` may fail to resolve.

Checklist

When converting a spec to Bikeshed:

1. **Inventory all `<dfn>` elements** in the original spec and note their IDs 2. **Check for cross-spec references** — search other W3C specs that link to this spec's anchors (use [xref](https://respec.org/xref/) or grep the spec's URL in other repos) 3. **Add explicit `id` attributes** to every `<dfn>` that had an ID in the original, matching the original ID exactly 4. **Verify after conversion** — build the Bikeshed output and confirm all anchors from the original spec still resolve 5. **Check `data-dfn-for` scoping** — Bikeshed uses `data-dfn-for` to scope definitions; make sure scoped dfns also retain their original IDs (e.g., `id="wall-clock-unsafe-current-time"` for `<dfn data-dfn-for="wall clock">unsafe current time</dfn>`)