The AIRTIVITY™ Study: A Study to Find Out Whether BI 1291583 Helps People With Bronchiectasis

Inclusion criteria: * Male or female participants. Woman of childbearing potential (WOCBP) must be ready and able to use highly effective methods of birth control per International Council of Harmonisation (ICH) M3 (R2) that result in a low failure rate of less than 1 % per year when used consistently and correctly, as well as one barrier method. A list of contraception methods meeting these criteria is provided in the participant information. * Signed and dated written informed consent and assent, if applicable, prior to admission to the study, in accordance with GCP and local legislation. * Age of participants when signing the informed consent/assent ≥12 years. \-- Adolescents need to weigh at least 35 kg at Visit 1. * Clinical history consistent with bronchiectasis (e.g. cough, chronic sputum production, recurrent respiratory infections) and investigator confirmed diagnosis of bronchiectasis by CT scan where bronchiectasis has been documented by a radiologist. Participants whose past CT scan image records are not available will undergo a chest CT scan during Screening. Historical scans must not be older than five years. * Adult participants should be able to produce sputum for Pseudomonas aeruginosa assessment during the screening period. * History of documented pulmonary exacerbations requiring antibiotic treatment. In the 12 months before Visit 1, participants must have had either: * at least 2 exacerbations, or * at least 1 exacerbation and an St. George's Re…