Okay, I’ve tried just loading your file on my end and it’s taking forever, and it utterly fails trying to submit, probably because it’s taking so long to compile the data for submission that the browser doesn’t let it finish. Doesn’t help that the data it submits is about 50% larger than the original file.
I only ever tested this plugin with smaller files, with a few dozen entries max. I’ve encountered a number of people having trouble getting it to play nice with larger files. I’m starting to think this plugin was a futile endeavour.
The plugin is basically an attempt at a built-in version of this desktop app: https://poedit.net/download, I suggest making your change with that. Once you save the changes, you can either replace the one in the theme (and ditch my plugin), or use continue to use my plugin for it’s replacement feature, and place your modified version under “wp-content/pomo-editor/themes/kallyas/languages/” on the server, assuming the file is under a folder named “languages” in the theme’s folder. Assuming the directory structure matches, it should allow your changes to persist after updates to the theme, however if other stuff has been changed, you’ll need to repeat the process.