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kotlinlang

&gt; <https://github.com/JetBrains/kotlin/blob/master/compiler/fir/tree/src/org/jetbrains/kotlin/fir/extensions/FirExtensionSessionComponent.kt|FirExtensionSessionComponent>
&gt; Registers custom components in the FirSession to be used by other parts of the plugin.
Is this meant to let me replace my own extension functions defined on `FirSession`? Also am I missing something, or is that single sentence description actually the entire extent of the docs?

Session components could be anything you need. They are stored inside the session and can be accessed anywhere where the session is available.
One of the common usecases for them is to store various kinds of caches.