Questions & Answers about Dnes jsme sklidili úrodu, což je dobrá zpráva.
The ending -i shows that the subject is we and that the group is masculine animate or mixed, or it can sometimes be used in standard teaching examples as the default plural form learners first notice.
More broadly, Czech past participles change according to gender and number:
- sklidil = he harvested
- sklidila = she harvested
- sklidilo = it harvested
- sklidili = they/we harvested (masculine animate or mixed group)
- sklidily = they/we harvested (non-masculine animate group)
In this sentence, sklidili tells you the speaker is part of a plural subject: we.