Rocket.Chat/app/ui-message/client/messageBoxNotSubscribed.html

<template name="messageBoxNotSubscribed" args="_id">
	{{#if customTemplate}}
		{{> Template.dynamic customTemplate }}
	{{else}}
		{{#if canJoinRoom}}
			<div class="rc-message-box__join">
				{{{_ "you_are_in_preview_mode_of" room_name=roomName}}}

				<input type="password" name="joinCode" placeholder="{{_ 'Password'}}" class="rc-input__element rc-message-box__join-code">

				<button class="rc-button rc-button--primary rc-button--small rc-message-box__join-button js-join-code">{{_ "join"}}</button>
			</div>
		{{/if}}

		{{#if isAnonymousReadAllowed}}
			<div class="rc-button-group">
				<button class="rc-button rc-button--primary rc-button--small js-register">{{_ "Sign_in_to_start_talking"}}</button>
				{{#if isAnonymousWriteAllowed}}
					<button class="rc-button rc-button--small js-register-anonymous">{{_ "Or_talk_as_anonymous"}}</button>
				{{/if}}
			</div>
		{{/if}}
	{{/if}}
</template>