Exhibit 99.1
| Joint Filer Information | ||
| Name of Joint Filer: | Keystone International Acquisition Management LLC | |
| Address of Joint Filer: | c/o Keystone Acquisition Corp. 142 West 57th Street, 11th Floor New York, NY 10019 | |
| Relationship of Joint Filer to Issuer: | 10% Owner, Director | |
| Issuer Name and Ticker or Trading Symbol: | Keystone Acquisition Corp. [ KEYY] | |
| Date of Event Requiring Statement: (Month/Day/Year): | 06/02/2026 | |
| Name of Joint Filer: | Jae Hyun (James) Park | |
| Address of Joint Filer: | c/o Keystone Acquisition Corp. 142 West 57th Street, 11th Floor New York, NY 10019 | |
| Relationship of Joint Filer to Issuer: | 10% Owner, Director, Officer (Executive Chairman) | |
| Issuer Name and Ticker or Trading Symbol: | Keystone Acquisition Corp. [ KEYY] | |
| Date of Event Requiring Statement: (Month/Day/Year): |
06/02/2026 | |