The guidebook written by the Brazilian government regarding good practices in web development recommends using the following meta tags:
<meta name="target_country" content="br" />
<meta name="country" content="Brazil" />
It does not provide any explanation for why we should use them, though. The guidebook is a 10 years old document; there are visibly outdated codes there. However, that was not the case with those two meta tags: I could not find whether they are recommended or deprecated by W3C. I could not even find if they actually exist, to begin with.
Are the meta tags target_country and country useful? If so, what for? Are they endorsed by W3C, or considered a good practice by any other relevant institution, browser, social network etc.? Do they help increasing accessibility?
Remove them if allowed, they are not valid and serve no purpose.
These definitely aren't part of the current spec for HTML5, I would guess they are HTML4 (if they were even relevant then, people did like to make up meta tags!)
Over on the wiki I can see that both "country" and "target_country" do not exist.
If you really need to display some form of location data use geo.country or geo.region etc. However Google ignores these anyway. so I am unsure if they have much use.
The only thing that I can think they may have been relevant for was for identifying the language of the page, but in HTML 5 you should be using the lang attribute on the HTML tag anyway.