wasavi 0.6.598 or later can access local files on your machine by using Local file operator for wasavi (hereafter called LFO). This function is still experimental. If there is a problem, please make an issue.

• Install LFO from Google Web Store. Or see the source code of this small app.
• Run LFO. Following window would open:
  Then, push Change... button and set any directory on your local drive. The directory will be root for wasavi.
• Use local file path with file: prefix in wasavi:
  
  Or set file: prefix to default in options page:
  

wasavi 0.6.598 or later can access local files on your machine. Root directory of local file system is also root just as it is for wasavi. Topics about file: prefix are same as Chrome.

Unfortunately, wasavi for Presto Opera can not access local files.