A Study to Test Whether BI 3810477 Helps People With Idiopathic Pulmonary Fibrosis When Taken With or Without Standard Treatment

Inclusion Criteria: 1. Diagnosis of idiopathic pulmonary fibrosis (IPF). 2. Participants may be either: \- On stable monotherapy with nintedanib, pirfenidone, or nerandomilast for at least 12 weeks prior to Visit 1 and are planning to stay on this background treatment through the screening period and during the treatment period. OR \- Not currently on treatment with nintedanib, pirfenidone, or nerandomilast for at least 12 weeks prior to Visit 1 (i.e. either antifibrotic-treatment naïve or previously discontinued) and do not plan to start or re-start antifibrotic treatment during the screening or the treatment periods. 3. Patients with an extent of fibrosis ≥10% as per a high-resolution computed tomography (HRCT) of the chest performed within 12 months prior to Visit 1 or during the screening period (if not available) and confirmed by central review. 4. Patients with a forced vital capacity (FVC) ≥45% predicted at Visit 1. Predicted normal values will be calculated according to Global Lung Function Initiative (GLI). 5. Diffusing capacity of the lung for carbon monoxide (DLCO) ≥25% and \<80% of predicted normal corrected for haemoglobin (Hb) at Visit 1. 6. 40 years of age or older at the time of informed consent signature. 7. Signed and dated written informed consent in accordance with International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use - Good clinical Practice (ICH-GCP) and local legislation prior to admission to the trial. 8. Males or females of non-childbearing potential • A woman of non-childbearing potential is considered eligible for participation if nonfertile, i.e. postmenopausal (defined as no menses for 12 months without an alternative medical cause) or after permanent sterilisation which must have included a bilateral oophorectomy. Not eligible for the trial are women that still have the potential for future oocyte donation for in vitro fertilisation methods, including women that have had a hysterectomy or bilateral salpingectomy without bilateral oophorectomy. Tubal ligation is NOT a method of permanent sterilization. 9. Further inclusion criteria apply. Exclusion Criteria: 1. Acute exacerbation of idiopathic pulmonary fibrosis (IPF) within at least 12 weeks prior to Visit 1 and/or during the screening period (per investigator judgment). 2. Relevant airways obstruction (pre-bronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) \<0.7) at Visit 1. 3. Exclusion of patients with emphysema \>15 % of total lung volume on high-resolution computed tomography (HRCT) on central review. 4. In the opinion of the investigator, other clinically significant pulmonary abnormalities. 5. Lower respiratory tract infection requiring treatment within 4 weeks prior to Visit 1 and/or during the screening period. 6. Major surgery (major according to the investigator's assessment) performed within 12 weeks prior to randomisation or planned during the trial, e.g. hip replacement. 7. Any documented active or suspected malignancy or history of malignancy within 5 years prior to screening, except appropriately treated basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or in situ carcinoma of uterine cervix. 8. Cardiovascular comorbidities including: Severe hypertension (uncontrolled under treatment ≥160/100 mmHg at multiple occasions per investigator judgment) within 3 months of Visit 1, Myocardial infarction, stroke, or transient ischemic attack within 6 months of Visit 1, Unstable cardiac angina within 6 months of Visit 1. 9. Further exclusion criteria apply.