Contrary to what you might think, DTML isn't the only programming language available to you in Zope. Take a look at Zope Page Templates (ZPT), a template-based alternative that makes it easier for designers and developers to collaborate on Zope application development.
As you've already seen, this means "replace the content enclosed within the <title>
element with the result obtained by evaluating the TALES expression [template/title]".
When the template is rendered, this TALES expression will evaluate to the title of the current page, which will appear within the <title> tag, like this:
<title>Hello ZPT!</title>
The second statement is similar, except that this time, the element itself is
replaced, together with the content enclosed within it. When the page is rendered, the TAL statement
<h2>Welcome to <span tal:replace="here/title_or_id">content title or
id</span></h2>
will replace the <span>...</span> tags with the results of evaluating the
TALES expression within it, like this: