--- title: --- ```svelte ``` The `` element provides a place to specify per-component compiler options, which are detailed in the [compiler section](svelte-compiler#compile). The possible options are: - `immutable={true}` — you never use mutable data, so the compiler can do simple referential equality checks to determine if values have changed - `immutable={false}` — the default. Svelte will be more conservative about whether or not mutable objects have changed - `accessors={true}` — adds getters and setters for the component's props - `accessors={false}` — the default - `runes={true}` — forces a component into _runes mode_ (see the [Legacy APIs](legacy-overview) section) - `runes={false}` — forces a component into _legacy mode_ - `namespace="..."` — the namespace where this component will be used, most commonly "svg"; use the "foreign" namespace to opt out of case-insensitive attribute names and HTML-specific warnings - `customElement={...}` — the [options](custom-elements#Component-options) to use when compiling this component as a custom element. If a string is passed, it is used as the `tag` option ```svelte ```