Found it! : C:\Users\(DefaultUser)\AppData\Roaming\Opera Software\Opera Stable\IndexedDB
https_editor.construct.net_0.indexeddb.blob | 2.86 MB
https_construct-arcade.com_0.indexeddb.leveldb | 127 KB
https_editor.construct.net_0.indexeddb.leveldb | 83 KB
https_preview.construct.net_0.indexeddb.leveldb | 32 KB
https_account.construct.net_0.indexeddb.leveldb | 4 KB
Therse are all of the Folders I could find related to Construct 3. The .blob folder is what I assume stores the data of my projects (the rest are Log files), but as I thought, they are scattered in numeral partitioned sub-folders. So, if I were to quickly migrate my Construct projects to another computer which supports the same, Chromium file integration, I may simply backup the "IndexedDB" folder. Rather than to, export all of my projects for downloading as .c3p file one-by-one. Sure, uploading to cloud is the most time efficient (not when Uploading!) and safe way undisputably but I never was keen on real-time saving files to clouds, especially in video games that use Cloud for saving progress -- it just demolishes my internet for 30 seconds as I have slow upload speed on my network. I digress.
Although, backing up IndexedDB folder and importing to another computer may not works aswell (insert a computer-science pun here!), yet, I really do not want and need to test it out just now. Thanks for the information Ashley! You rock!