Chrome Tab Unloader
This browser extension gives you a simple button to unload the current tab, or all tabs. You might do this in order to save on system resources (RAM, CPU), or to make the tab quiet. Reload the tab just by clicking in its content area.
Placeholder page design
Reasons to make the placeholder page be what it is (a data:text/html
URI arranged a certain way):
I put the embedded URL near the beginning of the placeholder's URL,
with a minimum of escaping, so that you can copy it out yourself
if needed. The only character you might have to unescape is the
fragment # mark (%23) because putting that literally would
cause the rest of the data uri to be a fragment instead of HTML.
(Possibly I could end the embedded URL with
<script type="url">..url.. to not even have to escape the #?
If I handled properly the page itself's use of the # in its URL.)
I made the page work even if this extension isn't installed anymore, because it might end up in bookmarks or copied somewhere.
I made the page let you get to its target without Javascript, in case Javascript got turned off for that page somehow.
I made the page work even if you copy the URL to a new tab. Though unfortunately this has tension with preserving your browsing history when you don't copy the URL. In one choice, your tab "back" history gets longer every time you unload then load a page. In the other choice, if you copied around the data: URL, you might have to go "forward" after re-loading the page in order to actually get to the page. Maybe eventually there will be an API that makes this all work great.
The favicon is an embedded data: URI, instead of pointing to the original server favicon, for two reasons. It makes the favicon work without any network access, and it allows me to modify the favicon to make it easier to see that a tab is unloaded (e.g. making its color grayer).
Attribution
Icon is from wikimedia under CC-BY-SA 4.0 International.
Building
To get a .zip for the chrome web store,
git archive --format zip HEAD -o chrome-tab-unloader.zip