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

<form hx-boost="true" hx-sync="this:replace" hx-target="this" method="post" action="{{.Issue.Link}}/watch"
	{{if not $.IsSigned}}
		{{if $.Issue.IsPull}}
			data-tooltip-content="{{ctx.Locale.Tr "repo.subscribe.pull.guest.tooltip"}}"
		{{else}}
			data-tooltip-content="{{ctx.Locale.Tr "repo.subscribe.issue.guest.tooltip"}}"
		{{end}}
	{{end}}>
	<input type="hidden" name="watch" value="{{if $.IssueWatch.IsWatching}}0{{else}}1{{end}}">
	<button class="fluid ui button {{if not $.IsSigned}}disabled{{end}}">
		{{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>