RAR files are containers and can be used to deliver malware if the source is untrusted. Before opening:
Ecosystem Components - Rare Plant Diversity - Download the French ZIP (PDF, JPG) File through HTTP - Open Government Portal. Open Government (Canada) Download File B5C63449671B.rar
Use a service like VirusTotal to upload the file and check it against dozens of antivirus engines. RAR files are containers and can be used
Ecosystem Components - Rare Plant Diversity - Download the French ZIP (PDF, JPG) File through HTTP - Open Government Portal. Open Government (Canada) Download the French ZIP (PDF, JPG) File through HTTP Download File B5C63449671B.rar
If you found this on an official site like the Open Government Portal, it may be part of a technical dataset or geographic "Rare Plant Diversity" record.