svelte/packages/svelte/messages/client-warnings/warnings.md

hydration_attribute_changed

The %attribute% attribute on %html% changed its value between server and client renders. The client value, %value%, will be ignored in favour of the server value

hydration_html_changed

The value of an {@html ...} block changed between server and client renders. The client value will be ignored in favour of the server value

The value of an {@html ...} block %location% changed between server and client renders. The client value will be ignored in favour of the server value

hydration_mismatch

Hydration failed because the initial UI does not match what was rendered on the server

Hydration failed because the initial UI does not match what was rendered on the server. The error occurred near %location%

lifecycle_double_unmount

Tried to unmount a component that was not mounted

ownership_invalid_binding

%parent% passed a value to %child% with bind:, but the value is owned by %owner%. Consider creating a binding between %owner% and %parent%

ownership_invalid_mutation

Mutating a value outside the component that created it is strongly discouraged. Consider passing values to child components with bind:, or use a callback instead

%component% mutated a value owned by %owner%. This is strongly discouraged. Consider passing values to child components with bind:, or use a callback instead

state_proxy_equality_mismatch

Reactive $state(...) proxies and the values they proxy have different identities. Because of this, comparisons with %operator% will produce unexpected results. Consider using $state.is(a, b) instead