src/vs/workbench/contrib/extensions/browser/extensionsWorkbenchService.ts/ExtensionsWorkbenchService/canInstall
class ExtensionsWorkbenchService:	async canInstall(extension: IExtension): Promise<boolean> {
		if (!(extension instanceof Extension)) {
			return false;
		}

		if (extension.isMalicious) {
			return false;
		}

		if (extension.deprecationInfo?.disallowInstall) {
			return false;
		}

		if (!extension.gallery) {
			return false;
		}

		if (this.localExtensions && await this.localExtensions.canInstall(extension.gallery)) {
			return true;
		}

		if (this.remoteExtensions && await this.remoteExtensions.canInstall(extension.gallery)) {
			return true;
		}

		if (this.webExtensions && await this.webExtensions.canInstall(extension.gallery)) {
			return true;
		}

		return false;
	}