Swaziland has been renamed to Kingdom of eSwatini, it is Swazi meaning "place of the Swazi". But I'm pretty interested in the lowercase "e" starting the proper noun of eSwatini. I know in the west we have this with many of our tech pronouns, most notably with apple products like iPhone. But I'm wondering if this is part of Swazi syntax and is common in the language, or that it is a new addition to their written language?
The common rule for Swati and all of the Nguni languages rule for proper nouns is that you capitalize the initial letter of the "root", not the word. Sentence-initial capitalization on the other hand affects the first letter in the sentence. I put root in quotes because proper names can be formed from inflected verbs, which have subject prefixes, but those inflected verbs are treated as though they are autonomous roots. For example, uSibadle from /si-ba-dle/ "we will eat them". The initial vowel is called the "augment" in Bantu, and it is a feature of the noun class system, found in u-m-fana "boy", ba-fana or e-ba-fana "boys".
In the case of eSwatini, this is a locative, formed by adding e- to the un-augmented noun and suffixing -ini, so indvodza "man", endvodzeni. The suffix part is lexically omittable, e.g. ebusika "in winter", and is commonly left off of place names (eMbabane (the capital)), but not always eZulwini "the heavens").
As far as the history of spelling is concerned, Swati was more recently recognized as different from Zulu, and inherited writing practices from Zulu. Zulu has been written for longer: I don't know anything about the very earliest missionary works, and there are grammars from the mid 19th century. In Bryant's 1848 article "The Zulu language", citation names are given as e.g. Umpandi, Unyokhana, and Grout 1849 "The Zulu and other dialects of southern Africa" likewise gives Untaba, Ubalekhile. This may reflect author idiosyncracy, but today's idiosynracy is tomorrow's policy. In other words, there is some reason to think that the proper name rule is a more recent development, but when exactly is beyond me. The history of this convention is expertly discussed here.