forgejo/templates/repo/issue/view_content/sidebar/watch.tmpl

<div class="ui watching">
	<span class="text"><strong>{{ctx.Locale.Tr "notification.notifications"}}</strong></span>
	<div class="tw-mt-2">
		<form hx-boost="true" hx-sync="this:replace" hx-target="this" method="post" action="{{.Issue.Link}}/watch">
			<input type="hidden" name="watch" value="{{if $.IssueWatch.IsWatching}}0{{else}}1{{end}}">
			<button class="fluid ui button">
				{{if $.IssueWatch.IsWatching}}
					{{svg "octicon-mute" 16 "tw-mr-2"}}
					{{ctx.Locale.Tr "repo.issues.unsubscribe"}}
				{{else}}
					{{svg "octicon-unmute" 16 "tw-mr-2"}}
					{{ctx.Locale.Tr "repo.issues.subscribe"}}
				{{end}}
			</button>
		</form>
	</div>
</div>