I get the following warning when I try to install the extension : "Malicious extensions may cause problems and invade privacy." I prefer not to install it as long as'm not sure it's completely safe. One of the main reasons I like the old Opera is that I've never needed extensions or add-ons for it because everything was built-in.
For "Fit to Width" look at these screen dumps before and after enabling the function.
1) text isn't wrapping and can't be read without a lot of horizontal scrolling : http://img8.pixhost.org/images/143/34221976_too-wide.gif
2) text wraps and no horizontal scrollbar is needed to read the text : http://img8.pixhost.org/images/143/34221973_fit-to-width.gif
This happens only with smaller sites that have designers who don't know much about HTML.
Most people think Javascript isn't a threat but I know better. I just give a few articles about past problems and the incidents are increasing with time :-
[Many Chrome browser extensions do sneaky things - Computerworld - Opera]
For example, extensions can intercept Web requests from the browser and modify traffic and inject JavaScript into Web pages. http://www.computerworld.com/s/article/9250498/Many_Chrome_browser_extensions_do_sneaky_things?source=CTWNLE_nlt_security_2014-08-21
[Most Ironic Attack Ever Plants Malware On Websites Using PageFair Ad Service - Opera]
The PageFair hackers secretly replaced the fine JavaScript that pages usually serve with their own malware, which infected sites http://www.fastcompany.com/3053001/elasticity/most-ironic-attack-ever-plants-malware-on-websites-using-pagefair-ad-service
[Locky ransomware activity ticks up | Computerworld - Opera]
recent Locky spam contains an obfuscated JavaScript file, which if executed downloads the ransomware http://www.computerworld.com/article/3042617/security/locky-ransomware-activity-ticks-up.html
I might be a control freak and a bit paranoid, but I want to keep security risks as low as possible. I know many people don't care about their privacy or malware but I do. I enable JavaScript only when strictly necessary. I choose sites on the basis of their content and navigability. Most of the time JS isn't necessary at all. For instance, the m-version of Yahoo works without JS on my PC.