The specific figure of "121 MB" is a significant red flag. The possible explanations for this file size include:

There is no historical version of Opera Mini that legitimately matches a file size of 121 MB . This size is closer to a modern desktop browser installer (like Opera GX or Chrome) or a software suite, rather than a lightweight mobile browser.

Old Opera Mini is a legacy mobile web browser known for fast browsing on low‑spec devices and strong data compression. The 121 MB portable package includes the classic Opera Mini binary plus necessary resources, allowing you to run it without installation on compatible devices or emulators.