Desarrolle is the 3rd person imperative form of desarollar. Desarrolla is 3rd person present tense. So, it's not the imperative. You can say ''Develop that'' without it being a command. Perhaps this is just a polite request to someone to ''Develop that''? Hard to know as it stands w/o the benefit of context.
Are you sure for desarrolar? The imperative affirmative is, desarrolla (tú) made with 3rd pers indicative presente sing.. and desarrolle (ella), desarrolemos (nosotros), desarrollad (vosotros), desarrollen (ellos) , But in a negative sentence, you have to use subjonctive present to form imperative, negative. desarroles, desarrole, desarrollemos, (with no) etc. http://conjugueur.reverso.net/conjugaison-espagnol-verbe-desarrollar.html
You can say, ella desarrolla eso, she develops that, indicative present. You can also say, desarrolla eso, (tú) imperative, for develop that. Without the context, how can we know for sure. In the link Reverso, it says desarrolla tú. I don't understand why you say that the sentence in Spanish is present tense, because in imperative , it's written the same way in reverso. Please someone, explain that to me.