What does "International Journal of" mean or imply? It can be argued in this day and age that virtually all academic journals are international, since they are online. Anyone with an internet connection can read and submit their work to journals, independent of their physical location or nationality (assuming they are not paywalled, which is still an international issue). The editorial boards of most reputable journals are international, and so are the reviewers. Even the companies that dominate the academic publishing are multi-national entities. Despite this, many journals include the term international in their name, usually in the form: International Journal of [Something].

What does it mean or imply for an academic journal to be international and so entitled?

Does it mean that the founders of the journal were an international team? Does signify that its policies somehow promote internationality among the journal's editorial board, reviewers, and/or paper authors? Does it pertain to the journal's policy in selecting content to avoid focusing on the issues relevant to a locale and reflect a culturally diverse range of concerns? Is it merely a historical artifact from back when being international was a significant achievement, no longer practiced by founders of new journals?
It means nothing, as mentioned in the comments. A new journal must take a different name from existing ones, but usually wants to convey by its title what its subject is, e.g. Finance. If "Journal of Finance" is taken, one option is to name the new journal "International Journal of Finance". There are other options: "Journal of Financial Studies", "Review of Finance", "Finance Bulletin", "Finance Advances" or simply "Finance".

There is the marketing aspect that the journal name should sound fancy and intellectual, so "Blah Finance" is not a common title choice.