| book_path: /_book.yaml | 
 | project_path: /_project.yaml | 
 |  | 
 | title: Extending Bazel | 
 | landing_page: | 
 |   header: | 
 |     hide_lower_section: true | 
 |   custom_css_path: /bazel.css | 
 |  | 
 |   rows: | 
 |   # Hero Row | 
 |   - options: | 
 |     - description-50 | 
 |     - hero | 
 |     - large-headings | 
 |     - no-image-background | 
 |     classname: bazel-hero bazel-hero-full-bleed-light | 
 |     items: | 
 |     - classname: bazel-hero | 
 |       image_path: /images/extend.svg | 
 |       heading: > | 
 |         Extending Bazel | 
 |       description: > | 
 |         Maximize Bazel's power through advanced concepts and extensions. | 
 |  | 
 |   # Jumpdown Row | 
 |   - options: | 
 |     - centered-header | 
 |     - large-headings | 
 |     - padding-large | 
 |     classname: bazel-jumpdown-row | 
 |     custom_html: > | 
 |       <a href="#concepts">Concepts<span class="material-icons">arrow_downward</span> | 
 |       </a> | 
 |       <a href="#writing-rules">Writing rules<span class="material-icons"> | 
 |       arrow_downward</span></a> | 
 |       <a href="#distributing-rules">Distributing rules<span class="material-icons">arrow_downward</span></a> | 
 |       <a href="#design-docs">Design docs<span class="material-icons">arrow_downward</span></a> | 
 |       <a href="#apis">APIs<span class="material-icons">arrow_downward</span></a> | 
 |  | 
 |   # Concepts row | 
 |   - options: | 
 |     - centered-header | 
 |     - cards | 
 |     background: white | 
 |     heading: Concepts | 
 |     description: > | 
 |       Understand concepts like rules and macros to extend Bazel's capabilities. | 
 |     items_across: 4 | 
 |     items: | 
 |     - heading: Overview | 
 |       path: /extending/concepts/ | 
 |     - heading: Rules | 
 |       path: /extending/rules | 
 |     - heading: Symbolic macros | 
 |       path: /extending/macros | 
 |     - heading: Legacy macros | 
 |       path: /extending/legacy-macros | 
 |     - heading: Depsets | 
 |       path: /extending/depsets | 
 |     - heading: Aspects | 
 |       path: /extending/aspects | 
 |     - heading: Repository rules | 
 |       path: /extending/repo | 
 |     - heading: Configurations | 
 |       path: /extending/config | 
 |  | 
 |   # Writing rules row | 
 |   - options: | 
 |     - centered-header | 
 |     - cards | 
 |     background: white | 
 |     heading: Writing rules | 
 |     description: > | 
 |       Write custom rules and macros to customize Bazel to your needs. | 
 |     items_across: 4 | 
 |     items: | 
 |     - heading: Creating a rule | 
 |       path: /rules/rules-tutorial | 
 |     - heading: Creating a symbolic macro | 
 |       path: /rules/macro-tutorial | 
 |     - heading: Creating a legacy macro | 
 |       path: /rules/legacy-macro-tutorial | 
 |     - heading: Creating custom verbs | 
 |       path: /rules/verbs-tutorial | 
 |     - heading: Starlark language | 
 |       path: /rules/language | 
 |     - heading: Starlark style guide | 
 |       path: /rules/bzl-style | 
 |     - heading: Challenges | 
 |       path: /rules/challenges | 
 |     - heading: Writing rules for Windows | 
 |       path: /rules/windows | 
 |     - heading: Example rules | 
 |       path: https://github.com/bazelbuild/examples/tree/HEAD/rules | 
 |  | 
 |   # Distributing rules row | 
 |   - options: | 
 |     - centered-header | 
 |     - cards | 
 |     background: white | 
 |     heading: Distributing rules | 
 |     description: > | 
 |       Share your custom rules to your project or the Bazel community. | 
 |     items_across: 4 | 
 |     items: | 
 |     - heading: Testing rules | 
 |       path: /rules/testing | 
 |     - heading: Lint | 
 |       path: https://github.com/bazelbuild/buildtools/tree/master/buildifier | 
 |     - heading: Optimizing performance | 
 |       path: /rules/performance | 
 |     - heading: Deploy rules | 
 |       path: /rules/deploying | 
 |     - heading: Document rules with Stardoc | 
 |       path: https://github.com/bazelbuild/stardoc | 
 |  | 
 |   # Design docs row | 
 |   - options: | 
 |     - centered-header | 
 |     - cards | 
 |     background: white | 
 |     heading: Design docs | 
 |     description: > | 
 |       Academic or conceptual materials on advanced Bazel concepts. | 
 |     items_across: 4 | 
 |     items: | 
 |     - heading: Platforms | 
 |       path: /extending/platforms | 
 |     - heading: Execution groups | 
 |       path: /extending/exec-groups | 
 |     - heading: Automatic execution groups | 
 |       path: /extending/auto-exec-groups | 
 |     - heading: Toolchains | 
 |       path: /extending/toolchains | 
 |  | 
 |   # APIs row | 
 |   - options: | 
 |     - centered-header | 
 |     - cards | 
 |     background: white | 
 |     heading: APIs | 
 |     description: > | 
 |       Connect Bazel with these API libraries. | 
 |     items_across: 4 | 
 |     items: | 
 |     - heading: Build file API | 
 |       path: /rules/lib/starlark-overview |